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HomeMy WebLinkAboutDERR-2025-000651Stantec Consulting Services Inc. 2890 East Cottonwood Parkway Suite 300, Salt Lake City UT 84121-7283 January 22, 2025 File: 203721870 Attention: Nicole Chavez Utah Department of Environmental Quality Division of Environmental Response and Remediation 195 North 1950 West, 1st Floor P.O. Box 144840 Salt Lake City, Utah 84116 Reference: 7-Eleven Store No. 27074 – Quarterly Groundwater Monitoring Report 3185 Harrison Boulevard, Ogden, Utah Facility ID 1200120, Release Site NXK Dear Ms. Chavez, Stantec is pleased to present this Quarterly Groundwater Monitoring Report on behalf of 7-Eleven, Inc. (7-Eleven) for 7-Eleven Store No. 27074 (the Site) located at 3185 Harrison Boulevard Ogden, Utah (Figure 1). The Utah Department of Environmental Quality (UDEQ), Division of Environmental Response and Remediation (DERR) refers to the Site as Facility ID 1200120, Release Site NXK. This report presents groundwater monitoring and sampling results for the fourth quarter of 2024. Four quarterly groundwater monitoring and sampling events were approved under Work Plan and Budget (WP&B) NXK-07. The objectives of quarterly groundwater monitoring and sampling are to further assess dissolved petroleum hydrocarbon concentration trends and seasonal groundwater level fluctuations associated with the Site following the March 2021 remedial excavation. This report also presents additional desktop study results assessing the possibility of off-site petroleum hydrocarbon sources contributing to the unexpected dissolved petroleum hydrocarbon concentration increases observed at the Site beginning in 2023. BACKGROUND 7-Eleven has leased the southern portion of the property since 1986 and operated a 7-Eleven convenience store with former retail sales of gasoline. The former underground storage tank (UST) system was located in the southeast side of the property (Figure 1) and consisted of three 10,000-gallon gasoline USTs and two product dispensers formerly used to distribute various grades of unleaded gasoline fuel. The northern portion of the property is occupied by an out-of-service automotive service facility, most recently In’ n’ Out Auto Clinic. The facility was previously operated as a Minit Lube, and a petroleum release from this facility (Release Site IPT) was discovered during the closure of two 3,000-gallon new oil USTs and one 3,000-gallon used oil UST on June 24, 1994. The former Minit Lube USTs were in the northwest portion of the property (behind the automotive service facility) and were closed by removal. Wasatch Environmental (Wasatch) conducted a limited subsurface investigation (LSI) on April 23, 2020, on behalf of the Utah Transit Authority (UTA). Residual impacts from Release Site IPT appeared to be present January 22, 2025 Page 2 of 6 Re: 7-Eleven Store No. 27074 – Quarterly Groundwater Monitoring Report 3185 Harrison Boulevard, Ogden, Utah Facility ID 1200120, Release Site NXK based on the analytical results of a groundwater sample collected from a temporary well-point within the former Minit Lube UST basin (west of the current automotive service facility building). The sample contained concentrations of total petroleum hydrocarbons as gasoline range organics (TPH-GRO) and TPH as diesel range organics (TPH-DRO) above the Initial Screening Levels (ISLs) developed by the UDEQ-DERR Leaking Underground Storage Tank (LUST) Section. The LSI also identified a release that appeared to be related to the 7-Eleven UST basin, and Stantec reported a petroleum release to the UDEQ-DERR on May 11, 2020. Soil and groundwater analytical results presented in the Wasatch LSI report indicated petroleum hydrocarbon concentrations west and south of the 7-Eleven UST basin exceeded the ISLs and Tier 1 Screening Levels (TSLs) developed by the UDEQ- DERR LUST Section. Based on these results, the UDEQ-DERR assigned Release Site NXK to the Site and requested a subsurface investigation WP&B NXK-01 was approved on September 30, 2020, and Stantec conducted the subsurface investigation (SI) on October 26 and 27, 2020 (with groundwater sampling conducted on November 12, 2020). Based on the results of the SI, benzene was reported above the ISL in a soil sample collected from the soil boring advanced to install monitoring well MW-2. TPH-GRO was reported above the ISL in a soil sample collected from the soil boring advanced to install MW-4. Groundwater analytical results indicated dissolved concentrations of benzene, ethylbenzene, TPH-GRO, and TPH-DRO exceeded their respective ISLs and/or TSLs in samples collected west and south of the UST basin (MW-1, MW-2, MW-3, and MW-4), and groundwater impacts extended beyond the property boundaries to the south. The UST system was closed by removal on March 2, 2021. A remedial excavation was then completed from March 3 through 5 under WP&B NXK-03. Petroleum containing soil (PCS) was removed from the UST excavation as part of UST closure, and the excavation floor was extended an additional 1.5 to 2 feet beyond the interface of backfill and native soils to remove additional PCS. Excavated soils were screened on site using a photoionization detector, and PCS was segregated for disposal. Non-impacted soils were used as backfill, and additional imported fill was also needed to fill and achieve compaction within the UST excavation. Approximately 180-tons of PCS were disposed of as non-hazardous waste at the ET Technologies Soil Regeneration Site at the Salt Lake Valley Landfill. Under WP&B NXK-02, Stantec conducted quarterly monitoring between the second quarter of 2021 and the first quarter of 2022. Dissolved petroleum hydrocarbon concentrations generally decreased during this time but remained above ISLs in MW-1 and MW-4 and TSLs in MW-2. On April 8, 2022, Stantec oversaw the abandonment of groundwater monitoring wells MW-2, MW-4, MW-5, and MW-6 to accommodate UTA BRT Project construction. Well abandonment activities were conducted according to WP&B NXK-04. As of fall 2022, UTA BRT Project construction had progressed to the point that replacement groundwater monitoring well locations could be proposed. On February 7 and 8, 2023, Stantec oversaw the installation of replacement groundwater monitoring wells MW-2R, MW-5R, MW-8, and MW-9 and conducted soil logging and sampling activities. These activities were conducted according to WP&B NXK-05. Due to the impacts of the UTA BRT project to the property, 7-Eleven ceased operations at this store in July 2023. The convenience store building is currently vacant. Stantec retains environmental access to manage Release Site NXK. January 22, 2025 Page 3 of 6 Re: 7-Eleven Store No. 27074 – Quarterly Groundwater Monitoring Report 3185 Harrison Boulevard, Ogden, Utah Facility ID 1200120, Release Site NXK Work conducted under WP&Bs NXK-01 through NXK-06 were previously reported to the UDEQ-DERR in the following reports.  Subsurface Investigation Report, 7-Eleven Store No. 27074, dated December 15, 2020.  UST System Closure and Remedial Excavation Report, 7-Eleven Store No. 27074, dated April 28, 2021.  Quarterly Groundwater Monitoring Report, 7-Eleven Store No. 27074 documents, dated August 2, 2021, November 2, 2021, February 2, 2022, and May 2, 2022.  Monitoring Well Abandonment Report, 7-Eleven Store No. 27074, dated July 8, 2022.  Groundwater Monitoring Well Installation Report, 7-Eleven Store No. 27074, dated March 30, 2023.  Quarterly Groundwater Monitoring Report, 7-Eleven Store No. 27074, dated April 24, 2023.  Quarterly Groundwater Monitoring Report, 7-Eleven Store No. 27074, dated July 24, 2023.  Quarterly Groundwater Monitoring Report, 7-Eleven Store No. 27074, dated October 24, 2023.  Quarterly Groundwater Monitoring Report, 7-Eleven Store No. 27074, dated January 24, 2024.  Quarterly Groundwater Monitoring Report, 7-Eleven Store No. 27074, dated July 23, 2024.  Quarterly Groundwater Monitoring Report, 7-Eleven Store No. 27074, dated October 22, 2024. GROUNDWATER MONITORING METHODS On December 11, 2024, static groundwater levels were gauged to the nearest one hundredth of a foot using a battery-powered product/water interface probe. Free product was not encountered in any of the monitoring wells. Monitoring wells MW-3, MW-5R, and MW-7 were sampled on December 11, 2024, and MW-1, MW-2R, MW-8, and MW-9 were sampled on December 12, 2024. The pumping rate for each well was determined in the field based on an attempt to limit drawdown within the well to one foot or less. Parameters were collected using either an AquaTroll 500 equipped with temperature/ conductivity, potential hydrogen (pH)/oxidation reduction potential (ORP), dissolved oxygen (DO), and turbidity probes, or a YSI 556 equipped with temperature/conductivity, pH/ORP, and DO probes. Parameters were recorded on the appropriate time interval necessary to fully replace the volume of the flow-through cell between readings. Purging continued until three consecutive readings were within the stabilization conditions detailed in WP&B NXK-07. Purged groundwater was thin spread on the surface near each well location. Wells were purged via peristaltic pump and disposable one-quarter inch poly sample tubing. Sample tubing was disconnected from the flow-through cell prior to sample collection. Groundwater samples were decanted into five 40-milliliter (mL) glass volatile organic analysis (VOA) containers containing hydrochloric acid (HCl) preservative. VOAs were filled in a manner to minimize sample volatilization and remove all headspace. Samples were then labeled with the sample identification, collection date, and time, and placed into an ice chilled cooler for delivery to the project laboratory under chain-of-custody (COC) documentation. Stantec also collected/submitted the following quality assurance/quality control (QA/QC) samples.  Blind field duplicate (DUP-01) from MW-1  Trip blank Samples were submitted for analysis of methyl tertiary-butyl ether, benzene, toluene, ethylbenzene, total xylenes, and naphthalene (MBTEXN) by United States Environmental Protection Agency (EPA) Method January 22, 2025 Page 4 of 6 Re: 7-Eleven Store No. 27074 – Quarterly Groundwater Monitoring Report 3185 Harrison Boulevard, Ogden, Utah Facility ID 1200120, Release Site NXK 8260B and TPH-GRO and TPH-DRO by EPA Method 8015. The trip blank was only analyzed for volatile organic compounds (VOCs) by EPA Method 8260B. All analyses were performed by Pace Analytical National (Pace) located in Mount Juliet, Tennessee. Laboratory report and chain-of-custody documentation are included as Attachment 1. GROUNDWATER MONITORING RESULTS On December 11, 2024, shallow groundwater beneath the Site was measured at depths ranging from 10.81 (MW-1) to 13.34 (MW-3) feet below top of casing (TOC). Each depth to groundwater measurement was converted to a relative groundwater elevation using the calculated relative TOC elevation of the monitoring well. A groundwater elevation contour map is provided as Figure 2. Isoconcentration maps for dissolved benzene, TPH-GRO, and TPH-DRO are provided as Figure 3, Figure 4, and Figure 5, respectively. Groundwater analytical results are summarized in Table 1. The fourth quarter 2024 field and analytical results are summarized below.  Shallow groundwater beneath the Site appears to flow towards the southwest at a local hydraulic gradient of approximately 0.06 feet per foot (as estimated between wells MW-5R and MW-7).  Groundwater elevations across the site decreased between the September 2024 and December 2024 monitoring events.  For the groundwater sample collected from MW-1, the dissolved benzene, ethylbenzene, TPH-GRO and TPH-DRO concentrations exceeded the respective ISLs.  For the groundwater sample collected from MW-2R, the dissolved TPH-DRO concentration exceeded the ISL. The dissolved benzene and TPH-GRO concentrations were below the respective ISLs.  The dissolved TPH-DRO concentrations in MW-3, MW-7, MW-8, and MW-9 all remain below the ISL.  Relative percent differences calculated between the MW-1 and DUP-01 sample analytical results were within generally accepted standards except for that of TPH-GRO, which has a relative percent difference of 43%. The MW-1 and DUP-01 samplers were analyzed in different TPH-GRO batches by Pace; the MW-1 TPH-GRO result reported by Pace was from an analysis batch ran two days later and at a dilution of five.  No petroleum hydrocarbons were detected at concentrations above laboratory RLs in the trip blank.  All other petroleum hydrocarbon concentrations were either below ISLs or were not detected above laboratory RLs.  All laboratory RLs were below the respective ISLs for this sampling event. CONTINUED OFF-SITE SOURCE DESKTOP STUDY Three data gaps were identified in the summary of the off-site source desktop study submitted with the previous quarterly groundwater monitoring report:  The nature of the original commercial structure first observed at the Site as of 1962 aerial photography could not be distinguished with certainty.  Whether or not diesel was associated with the original commercial structure was unknown.  Whether or not additional petroleum releases were recorded for the former 7-Eleven or former Minit Lube properties was not researched. January 22, 2025 Page 5 of 6 Re: 7-Eleven Store No. 27074 – Quarterly Groundwater Monitoring Report 3185 Harrison Boulevard, Ogden, Utah Facility ID 1200120, Release Site NXK In an effort to address the first two of these data gaps, Stantec ordered fire insurance maps and city directories for the Site area from Light Box EDR (EDR), a due diligence data provider. EDR could not provide fire insurance maps for the Site area, and the receipt of the city directories package was pending as of the writing of this report. Stantec will include any findings related to the nature of the original on-site commercial structure and presence of diesel at that structure from review of the city directories in the groundwater monitoring report for the first quarter of 2025. As documented in the previous groundwater monitoring report, the UDEQ interactive map did not document any USTs with significant release histories, petroleum related environmental incidents, voluntary cleanup program sites, CERCLA sites, or brownfields upgradient of the Site. After additional review of the UDEQ Environmental Interactive Map, no other on-site releases are documented for either the former 7-Eleven or former Minit Lube properties. CONCLUSIONS AND RECOMMENDATIONS The information compiled for the desktop study to date does not indicate a high potential for an off-site or separate on-site source of petroleum that may be impacting current Site conditions. The groundwater levels measured in 2024 followed the seasonal trend of high in the spring and low in early winter before snowmelt. The overall water levels in 2024 were higher than those in previous years. The dissolved petroleum hydrocarbon concentrations at MW-1 and MW-2 appeared to respond differently to the high water levels: the overall concentrations at MW-1 were higher in 2024 than in previous years, whereas the concentrations at MW-2 have mostly attenuated in 2024. This could be an indication that MW-1 is closer to the residual petroleum hydrocarbon source mass than MW-2, and the dissolved concentrations at MW-1 tend to go up as the water table rises and comes in contact with the source mass. Dissolved petroleum hydrocarbon concentrations versus time for select wells are shown in the attached Graphs. The groundwater table across the Site has shown an increasing trend since March 2023; this is the same period of time over which dissolved petroleum hydrocarbon concentrations have become more variable. More consistent dissolved petroleum hydrocarbon concentrations may once again be observed after the water table stabilizes following the maximum groundwater elevation conditions observed in June 2024. One quarterly groundwater monitoring event remains under WP&B NXK-07; however, based on the current dataset, it appears that any upgradient dissolved petroleum hydrocarbon concentrations above screening levels attenuate before reaching downgradient wells. Stantec will likely recommend closure of Release Site NXK following the first quarter of 2025 groundwater monitoring event. LIMITATIONS AND CERTIFICATION The conclusions in the Report titled 7-Eleven Store No. 27074 – Quarterly Groundwater Monitoring Report are Stantec’s professional opinion, as of the time of the Report, and concerning the scope described in the Report. The opinions in the document are based on conditions and information existing at the time the scope of work was conducted and do not take into account any subsequent changes. The Report relates solely to the specific project for which Stantec was retained and the stated purpose for which the Report was prepared. The Report is not to be used or relied on for any variation or extension of the project, or for any other project or purpose, and any unauthorized use or reliance is at the recipient’s own risk. January 22, 2025 Page 6 of 6 Re: 7-Eleven Store No. 27074 – Quarterly Groundwater Monitoring Report 3185 Harrison Boulevard, Ogden, Utah Facility ID 1200120, Release Site NXK Stantec has assumed all information received from 7-Eleven (the “Client”) and third parties in the preparation of the Report to be correct. While Stantec has exercised a customary level of judgment or due diligence in the use of such information, Stantec assumes no responsibility for the consequences of any error or omission contained therein. This Report is intended solely for use by the Client in accordance with Stantec’s contract with the Client. While the Report may be provided by the Client to applicable authorities having jurisdiction and to other third parties in connection with the project, Stantec disclaims any legal duty based upon warranty, reliance or any other theory to any third party, and will not be liable to such third party for any damages or losses of any kind that may result. If you have any questions or require any additional information, please contact Anna Skinner via the contact information provided below. Regards, Stantec Consulting Services Inc. Ally Auffermann, PE Environmental Engineer Phone: (801) 617 3211 ally.auffermann@stantec.com Anna Skinner Project Manager Certified UST Consultant #CC0271 Phone: (801) 743 4815 anna.skinner@stantec.com Attachments: Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Table 1 Graph 1 Graph 2 Graph 3 Graph 4 Graph 5 Graph 6 Graph 7 Attachment 1 Laboratory Report and Chain-of-Custody Documentation c. File / 7-Eleven Inc. John Wainwright, Stantec Site Plan Groundwater Elevation Contour Map December 2024 Dissolved Benzene Isoconcentration Map December 2024 Dissolved TPH-GRO Isoconcentration Map December 2024 Dissolved TPH-DRO Isoconcentration Map December 2024 Groundwater Analytical Results MW-1 Select Concentration vs. Time Graphs MW-2/2R Select Concentration vs. Time Graphs MW-3 Select Concentration vs. Time Graphs MW-5/5R Select Concentration vs. Time Graphs MW-7 Select Concentration vs. Time Graphs MW-8 TPH-DRO Concentration vs. Time Graph MW-9 TPH-DRO Concentration vs. Time Graph FIGURES MW-1 MW-3 MW-7 3200 SOUTH HA R R I S O N B O U L E V A R D FORMER CANOPY/ DISPENSERS CONVENIENCE STORE BUILDING AUTOMOTIVE SERVICE FACILITY T T ELEVEN FORMER PLANTERPLANTER UE UE UE UE UE UE UE UTILITY POLE STREET LIGHT PL A N T E R STORE NO. 27074 FORMER UST BASIN FORMER SIGN FORMER PLANTER FORMER PLANTER FORMER PLANTER FO R M E R PL A N T E R MW-6 MW-2 MW-2R MW-9 MW-8 MW-5R MW-5 MW-4 203721870 STA AMS JPW 03/20/23 1SITE PLAN STORE #27074 3185 HARRISON BOULEVARD OGDEN, UTAH FOR: JOB NUMBER:DRAWN BY:CHECKED BY:APPROVED BY:DATE: FILEPATH:C:\Users\SAguinaldo\Desktop\2023\SLC\203721870\FIG 2_7-11_27074_SITE PLAN_03-20-2023.dwg | Layout Tab: 1 | Drafter: SAguinaldo | Mar 22, 2023 at 14:43 FIGURE: No warranty is made by Stantec Consulting Services Inc. as to the accuracy, reliability, or completeness of these data. Original data were compiled from various sources. This information may not meet National Map Accuracy Standards. This product was developed electronically, and may be updated without notification. Any reproduction may result in a loss of scale and or information. N ELEVEN PHONE: 2890 E COTTONWOOD PKWY, STE 300 SALT LAKE CITY, UTAH (801) 261-0090 LEGEND T UE MONITORING WELL LOCATION TELEPHONE LINE GAS LINE OVERHEAD ELECTRICAL LINE BELOW GROUND ELECTRICAL LINE WATER LINE 0 30 60 APPROXIMATE SCALE IN FEET ABANDONED MONITORING WELL LOCATION 3200 SOUTH HA R R I S O N B O U L E V A R D FORMER CANOPY/ DISPENSERS CONVENIENCE STORE BUILDING AUTOMOTIVE SERVICE FACILITY T T PLANTER UE UE UE UE UE UE UE PL A N T E R STORE NO. 27074 FORMER UST BASIN FO R M E R PL A N T E R MW-6 MW-2 MW-5 MW-4 MW-2R 84.34 MW-9 87.33 MW-8 84.01 MW-5R 88.11 MW-7 82.26 MW-1 86.86 MW-3 84.19 203721870 STA AA JPW 01/16/2025 2STORE #27074 3185 HARRISON BOULEVARD OGDEN, UTAH FOR: JOB NUMBER:DRAWN BY:CHECKED BY:APPROVED BY:DATE: FILEPATH:C:\Users\SAguinaldo\Desktop\2025\SLC\4Q 2024\FIG 2_7-11_27074_GWE CONTOUR MAP.dwg | Layout Tab: 2 | Drafter: SAguinaldo | Jan 17, 2025 at 8:59 FIGURE: No warranty is made by Stantec Consulting Services Inc. as to the accuracy, reliability, or completeness of these data. Original data were compiled from various sources. This information may not meet National Map Accuracy Standards. This product was developed electronically, and may be updated without notification. Any reproduction may result in a loss of scale and or information. N ELEVEN PHONE: 2890 E COTTONWOOD PKWY, STE 300 SALT LAKE CITY, UTAH (801) 261-0090 ELEVEN 8 5 LEGEND T UE MONITORING WELL LOCATION TELEPHONE LINE GAS LINE OVERHEAD ELECTRICAL LINE BELOW GROUND ELECTRICAL LINE WATER LINE 0 30 60 APPROXIMATE SCALE IN FEET ABANDONED MONITORING WELL LOCATION GROUNDWATER ELEVATION CONTOUR MAP DECEMBER 2024 86.86 GROUNDWATER SURFACE ELEVATION (FEET ABOVE MEAN SEA LEVEL) GROUNDWATER ELEVATION CONTOUR (DASHED WHERE INFERRED)85 8 7 8 4 8 3 83 8 5 8 8 8 6 84 87 88 86 3200 SOUTH HA R R I S O N B O U L E V A R D FORMER CANOPY/ DISPENSERS CONVENIENCE STORE BUILDING AUTOMOTIVE SERVICE FACILITY T T PLANTER UE UE UE UE UE UE UE PL A N T E R STORE NO. 27074 FORMER UST BASIN FO R M E R PL A N T E R MW-6 MW-2 MW-5 MW-4 MW-2R 0.00415 MW-9 <0.00100 MW-8 <0.00100 MW-5R <0.00100 MW-7 <0.00100 MW-1 0.185MW-3 <0.00100 203721870 STA AA AS 01/16/2025 3STORE #27074 3185 HARRISON BOULEVARD OGDEN, UTAH FOR: JOB NUMBER:DRAWN BY:CHECKED BY:APPROVED BY:DATE: FILEPATH:C:\Users\SAguinaldo\Desktop\2025\SLC\4Q 2024\FIG 3_7-11_27074_BENZENE MAP.dwg | Layout Tab: 3 | Drafter: SAguinaldo | Jan 21, 2025 at 11:04 FIGURE: No warranty is made by Stantec Consulting Services Inc. as to the accuracy, reliability, or completeness of these data. Original data were compiled from various sources. This information may not meet National Map Accuracy Standards. This product was developed electronically, and may be updated without notification. Any reproduction may result in a loss of scale and or information. N ELEVEN PHONE: 2890 E COTTONWOOD PKWY, STE 300 SALT LAKE CITY, UTAH (801) 261-0090 LEGEND T UE MONITORING WELL LOCATION TELEPHONE LINE GAS LINE OVERHEAD ELECTRICAL LINE BELOW GROUND ELECTRICAL LINE WATER LINE ELEVEN 0 30 60 APPROXIMATE SCALE IN FEET ABANDONED MONITORING WELL LOCATION DISSOLVED BENZENE ISOCONCENTRATION MAP DECEMBER 2024 0.185 DISSOLVED BENZENE CONCENTRATION MILLIGRAMS PER LITER (mg/L) INFERRED BENZENE ISOCONCENTRATION CONTOUR (mg/L)0.005 <ANALYTE NOT DETECTED ABOVE THE SPECIFIED LABORATORY REPORTING LIMIT ELEVEN 0.005 3200 SOUTH HA R R I S O N B O U L E V A R D FORMER CANOPY/ DISPENSERS CONVENIENCE STORE BUILDING AUTOMOTIVE SERVICE FACILITY T T PLANTER UE UE UE UE UE UE UE PL A N T E R STORE NO. 27074 FORMER UST BASIN FO R M E R PL A N T E R MW-6 MW-2 MW-5 MW-4 MW-2R 0.552 MW-9 <0.100 MW-8 <0.100 MW-5R <0.100 MW-7 0.384 MW-1 2.74MW-3 0.349 203721870 STA AA AS 01/16/2025 4STORE #27074 3185 HARRISON BOULEVARD OGDEN, UTAH FOR: JOB NUMBER:DRAWN BY:CHECKED BY:APPROVED BY:DATE: FILEPATH:C:\Users\SAguinaldo\Desktop\2025\SLC\4Q 2024\FIG 4_7-11_27074_GRO ISOCON MAP.dwg | Layout Tab: 4 | Drafter: SAguinaldo | Jan 21, 2025 at 11:16 FIGURE: No warranty is made by Stantec Consulting Services Inc. as to the accuracy, reliability, or completeness of these data. Original data were compiled from various sources. This information may not meet National Map Accuracy Standards. This product was developed electronically, and may be updated without notification. Any reproduction may result in a loss of scale and or information. N ELEVEN PHONE: 2890 E COTTONWOOD PKWY, STE 300 SALT LAKE CITY, UTAH (801) 261-0090 LEGEND T UE MONITORING WELL LOCATION TELEPHONE LINE GAS LINE OVERHEAD ELECTRICAL LINE BELOW GROUND ELECTRICAL LINE WATER LINE 0 30 60 APPROXIMATE SCALE IN FEET ABANDONED MONITORING WELL LOCATION DISSOLVED TPH-GRO ISOCONCENTRATION MAP DECEMBER 2024 2.74 DISSOLVED TPH-GRO CONCENTRATION MILLIGRAMS PER LITER (mg/L) INFERRED TPH-GRO ISOCONCENTRATION CONTOUR (mg/L)1 <ANALYTE NOT DETECTED ABOVE THE SPECIFIED LABORATORY REPORTING LIMIT ELEVEN 1 3200 SOUTH HA R R I S O N B O U L E V A R D FORMER CANOPY/ DISPENSERS CONVENIENCE STORE BUILDING AUTOMOTIVE SERVICE FACILITY T T PLANTER UE UE UE UE UE UE UE PL A N T E R STORE NO. 27074 FORMER UST BASIN FO R M E R PL A N T E R MW-6 MW-2 MW-5 MW-2R 1.29 MW-9 0.313 MW-8 0.169 MW-5R 0.213 MW-7 0.600 MW-1 4.07 MW-3 0.790 MW-4 203721870 STA AA AS 01/16/2025 5STORE #27074 3185 HARRISON BOULEVARD OGDEN, UTAH FOR: JOB NUMBER:DRAWN BY:CHECKED BY:APPROVED BY:DATE: FILEPATH:C:\Users\SAguinaldo\Desktop\2025\SLC\4Q 2024\FIG 5_7-11_27074_DRO ISOCON MAP.dwg | Layout Tab: 5 | Drafter: SAguinaldo | Jan 21, 2025 at 11:23 FIGURE: No warranty is made by Stantec Consulting Services Inc. as to the accuracy, reliability, or completeness of these data. Original data were compiled from various sources. This information may not meet National Map Accuracy Standards. This product was developed electronically, and may be updated without notification. Any reproduction may result in a loss of scale and or information. N ELEVEN PHONE: 2890 E COTTONWOOD PKWY, STE 300 SALT LAKE CITY, UTAH (801) 261-0090 LEGEND T UE MONITORING WELL LOCATION TELEPHONE LINE GAS LINE OVERHEAD ELECTRICAL LINE BELOW GROUND ELECTRICAL LINE WATER LINE 0 30 60 APPROXIMATE SCALE IN FEET ABANDONED MONITORING WELL LOCATION DISSOLVED TPH-DRO ISOCONCENTRATION MAP DECEMBER 2024 4.07 DISSOLVED TPH-DRO CONCENTRATION MILLIGRAMS PER LITER (mg/L) INFERRED TPH-DRO ISOCONCENTRATION CONTOUR (mg/L)1 <ANALYTE NOT DETECTED ABOVE THE SPECIFIED LABORATORY REPORTING LIMIT ELEVEN 1 TABLE MTBE 11/12/20 12.64 85.03 <0.0100 0.321 <0.0100 0.646 0.143 0.116 1.97 3.68 06/24/21 13.22 84.45 <0.00250 0.0806 <0.00250 0.370 0.0588 0.0124 1.80 0.954 10/06/21 14.34 83.33 <0.00200 0.0549 <0.00200 0.261 0.0785 0.0159 1.86 0.634 12/20/21 14.78 82.89 <0.00100 0.0320 <0.00100 0.139 0.0357 0.00708 0.898 0.430 1 03/24/22 15.52 82.15 <0.00114 0.0447 <0.00114 0.138 0.0344 <0.00571 <0.571 0.656 03/09/23 14.45 83.22 <0.00100 0.00998 <0.00100 0.0377 0.0102 <0.00500 <0.500 0.895 06/07/23 12.27 85.40 <0.00100 0.00723 <0.00100 0.0259 0.00382 <0.00500 0.501 B 0.745 09/14/23 13.12 84.55 <0.00100 0.0129 <0.00100 0.205 0.0359 0.0379 <0.500 4.78 12/15/23 13.22 84.45 <0.0100 0.0117 <0.0100 0.187 0.0304 <0.0500 <5.00 <0.100 ~ 06/27/24 10.48 87.19 <0.0100 0.117 <0.0100 0.932 <0.0300 0.0590 J3 5.52 B 9.40 09/12/24 10.66 87.01 <0.0100 0.462 0.0386 1.97 0.352 0.325 J4 <5.00 8.07 12/12/24 10.81 86.86 <0.00505 0.185 <0.00500 0.959 <0.150 0.0516 Z1 2.74 4.07 11/12/20 12.35 85.03 <0.00250 0.153 0.00437 0.294 0.0440 0.0558 0.846 1.15 06/24/21 13.04 84.34 <0.00500 0.235 <0.00500 0.489 0.0196 0.0818 2.08 1.37 10/06/21 14.09 83.29 <0.0500 0.783 0.124 2.62 2.35 0.476 18.8 5.44 12/20/21 14.22 83.16 <0.0500 0.414 <0.0500 3.17 1.50 0.699 16.2 6.24 03/24/22 15.04 82.34 <0.00114 0.963 0.0282 2.21 0.637 <0.571 4.19 5.77 03/10/23 14.28 83.29 <0.0100 0.540 <0.0100 1.36 0.0738 0.0804 <5.00 8.12 06/07/23 12.26 85.31 <0.0100 0.745 0.0128 1.19 0.361 0.107 5.39 11.3 09/14/23 13.03 84.54 <0.0100 0.305 0.0377 1.18 2.18 0.250 6.17 4.31 12/15/23 13.08 84.49 <0.0100 0.364 0.0240 1.59 3.67 0.580 10.5 <0.100 ~ 06/27/24 10.22 87.35 <0.00505 0.0219 Z1 <0.0500 0.465 0.591 0.132 J3,Z1 25.1 B 1.44 09/12/24 10.31 87.26 <0.01000 0.0543 <0.01000 0.454 0.0572 0.0689 <5.00 4.86 12/12/24 13.21 84.36 <0.00500 0.00415 Z1 <0.00500 0.108 <0.0150 <0.0250 0.552 1.29 11/12/20 14.73 82.83 <0.000500 0.00294 <0.000500 <0.000500 <0.000500 <0.00100 0.325 0.357 06/24/21 14.98 82.58 <0.000500 0.00752 <0.000500 <0.000500 <0.000500 <0.00100 0.339 0.491 10/06/21 16.01 81.55 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.374 0.423 12/20/21 16.58 80.98 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.108 0.277 1 03/24/22 17.04 80.52 <0.00114 0.00311 <0.00114 <0.00114 <0.00343 <0.00571 <0.571 0.249 03/09/23 15.73 81.80 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 0.450 06/06/23 13.10 84.43 <0.00100 0.00271 <0.00100 <0.00100 <0.00300 <0.00500 0.950 1.27 J3 09/14/23 14.16 83.37 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 0.786 12/15/23 14.90 82.63 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 0.518 B 5.12 ~ 06/26/24 12.36 85.17 <0.00100 0.00221 <0.00100 0.0140 <0.00300 <0.00500 J3 0.616 B 0.786 09/12/24 12.99 84.54 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J4 <0.500 0.822 12/11/24 13.34 84.19 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 0.349 0.790 11/12/20 11.66 84.88 <0.0500 2.29 <0.0500 2.20 0.956 0.283 12.5 6.68 06/24/21 12.37 84.17 <0.0100 0.603 <0.0100 0.812 0.270 0.0300 4.65 4.00 10/06/21 13.69 82.85 <0.0100 0.312 <0.0100 0.741 0.199 0.0221 4.80 3.02 12/20/21 13.96 82.58 <0.00500 0.0449 <0.00500 0.437 0.00959 <0.0100 1.79 2.72 03/24/22 14.86 81.68 <0.00114 0.00768 <0.00114 0.134 <0.00343 <0.00571 <0.571 1.25 11/12/20 13.33 86.06 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.260 0.0515 06/24/21 14.07 85.32 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.178 <0.0517 10/06/21 15.36 84.03 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.298 0.0785 12/20/21 16.15 83.24 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.328 <0.0523 03/24/22 16.90 82.49 <0.00114 <0.00114 <0.00114 <0.00114 <0.00343 <0.00571 <0.571 <0.114 03/10/23 16.18 83.34 <0.00100 <0.00100 <0.00100 0.0173 0.142 0.00877 0.513 1.48 06/07/23 13.26 86.26 <0.00100 <0.00100 <0.00100 0.00778 0.0236 0.00758 0.574 1.80 09/14/23 14.07 85.45 <0.00100 <0.00100 <0.00100 0.00585 0.0297 0.0213 <0.500 1.17 12/15/23 14.35 85.17 <0.00100 <0.00100 <0.00100 0.00164 0.00481 <0.00500 <0.500 <0.100 ~ 06/26/24 10.77 88.75 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J3 <0.500 0.467 09/12/24 11.34 88.18 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J4 <0.500 0.331 12/11/24 11.41 88.11 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.100 0.213 11/12/20 14.66 85.34 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 <0.0500 <0.0476 06/24/21 15.30 84.70 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 <0.0500 <0.0509 10/06/21 16.36 83.64 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 <0.0500 <0.0537 12/20/21 16.70 83.30 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 <0.0500 <0.0510 03/24/22 17.24 82.76 <0.00114 <0.00114 <0.00114 <0.00114 <0.00343 <0.00571 <0.571 <0.114 0.2 0.005 1.0 0.7 10.0 0.7 1.0 1.0 0.2 0.3 3.0 4.0 10.0 0.7 10 10 Groundwater Analytical Results Table 1 3185 Harrison Boulevard, Ogden, Utah 7-Eleven Store No. 27074 Sample Location Date Depth to Groundwater (feet) Relative Groundwater Elevation (feet) TPH-DRO (mg/L)Total Xylenes Ethylbenzene TPH-GRO (mg/L)TolueneBenzene MBTEXN Compounds (mg/L) MW-2R UDEQ DERR Tier 1 Screening Level MW-4# MW-5# MW-6# UDEQ DERR Initial Screening Level MW-5R Naphthalene MW-1 MW-2# MW-3 fnl_dbs_27074_20241211-12.xlsx Water 1 of 3 Stantec Consulting Services Inc. MTBE Groundwater Analytical Results Table 1 3185 Harrison Boulevard, Ogden, Utah 7-Eleven Store No. 27074 Sample Location Date Depth to Groundwater (feet) Relative Groundwater Elevation (feet) TPH-DRO (mg/L)Total Xylenes Ethylbenzene TPH-GRO (mg/L)TolueneBenzene MBTEXN Compounds (mg/L) Naphthalene 11/12/20 14.05 81.02 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.386 0.433 06/24/21 14.28 80.79 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.428 0.381 10/06/21 15.08 79.99 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.536 0.371 12/20/21 15.43 79.64 <0.000500 <0.000500 <0.000500 <0.000500 <0.000500 <0.00100 0.693 0.479 1 03/24/22 15.79 79.28 <0.00114 <0.00114 <0.00114 <0.00114 <0.00343 <0.00571 0.856 0.458 03/09/23 14.75 80.25 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 0.855 1.24 06/07/23 12.11 82.89 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 0.829 1.09 J3 09/13/23 12.81 82.19 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 1.06 12/15/23 13.84 81.16 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 0.708 B 6.14 ~ 06/26/24 11.76 83.24 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J3 0.896 B 0.872 09/12/24 12.42 82.58 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J4 0.766 0.870 12/11/24 12.74 82.26 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 0.384 0.600 03/10/23 14.98 81.29 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 <0.100 06/06/23 12.60 83.67 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 0.258 J3 09/13/23 13.23 83.04 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 0.191 12/15/23 13.90 82.37 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 416 J7,~ 06/26/24 11.28 84.99 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J3 <0.500 0.125 09/12/24 11.78 84.49 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J4 <0.500 0.231 12/12/24 12.26 84.01 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.100 0.169 03/10/23 15.05 83.60 <0.00100 <0.00100 <0.00100 0.0132 <0.00300 <0.00500 <0.500 1.56 06/07/23 13.22 85.43 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 0.661 09/13/23 13.93 84.72 <0.00100 <0.00100 <0.00100 0.00785 0.0295 0.00805 <0.500 0.354 12/15/23 14.03 84.62 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.500 0.406 ~ 06/26/24 11.08 87.57 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J3 <0.500 0.413 09/12/24 11.11 87.54 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 J4 <0.500 0.432 12/12/24 11.32 87.33 <0.00100 <0.00100 <0.00100 <0.00100 <0.00300 <0.00500 <0.100 0.313 FD-1 (MW-2)06/24/21 -- --<0.00200 0.0557 <0.00200 0.261 0.0407 0.00665 1.25 0.954 RPD (%)-- -- -- --123%--61% 70% 170% 50% 36% FD-1 (MW-2)12/20/21 -- --<0.0500 0.533 <0.0500 3.09 1.41 0.832 14.4 5.32 RPD (%)-- -- ---- 25% -- 3% 6% 17% 12% 16% FD-1 (MW-2)03/24/22 -- --<0.00114 0.888 0.0282 2.06 0.735 0.203 4.08 5.68 RPD (%)-- -- ---- 8% 0% 7% 14% -- 3% 2% DUP-01 (MW-2R)03/10/23 -- --<0.00100 0.630 0.00531 1.47 0.0779 0.0602 Z1 2.03 7.10 RPD (%)-- -- ---- 15% -- 8% 5% 29% -- 13% DUP-01 (MW-2R)06/07/23 -- --<0.0500 0.784 <0.0500 1.33 0.366 <0.250 <25.0 12.1 RPD (%)-- -- ---- 5% -- 11% 1% -- -- 7% DUP-01 (MW-2R)09/14/23 -- --<0.0500 0.243 0.0470 Q 1.05 1.77 0.251 12.50 Q 1.11 RPD (%)-- -- ---- 23% 22% 12% 21% 0% 68% 118% DUP-01 (MW-2R)12/15/23 -- --<0.00100 0.338 Q,J2 0.0190 J2 1.36 Q,J2 3.00 Q,J2 0.405 10.8 2.97 ~ RPD (%)-- -- ---- 7% 23% 16% 20% 36% 3% -- DUP-01 (MW-2R)06/27/24 -- --<0.00100 0.0328 0.00231 0.512 Q 0.662 Q 0.185 J3 4.02 B 2.75 RPD (%)-- -- ---- 40% -- 10% 11% 33% 145% 63% DUP-01 (MW-2R)09/12/24 -- --<0.00100 0.0460 0.00367 0.420 0.0496 0.0704 <0.500 4.09 RPD (%)-- -- ---- 17% -- 8% 14% 2% -- 17% DUP-01 (MW-1)12/12/24 -- --<0.00100 0.158 0.00140 1.01 0.0163 0.0456 4.24 4.40 RPD (%)-- -- ---- 16% -- 5% -- 12% 43% 8% 0.2 0.005 1.0 0.7 10.0 0.7 1.0 1.0 0.2 0.3 3.0 4.0 10.0 0.7 10 10 Elevation* Screened Interval (feet) Total Well Depth (feet) 5 to 20 5 to 20 97.57 97.67 Relative Top (feet) of Casing 20 20 98.65 96.27 95.00 99.52 97.53 5 to 20 5 to 20 5 to 20 5 to 20 5 to 20 20 20 20 20 20 Well ID MW-9 MW-8 MW-7 UDEQ DERR Tier 1 Screening Level UDEQ DERR Initial Screening Level Q,Z1,J 2 MW-9 MW-8 MW-7 MW-5R MW-3 MW-2R MW-1 fnl_dbs_27074_20241211-12.xlsx Water 2 of 3 Stantec Consulting Services Inc. Groundwater Analytical Results Table 1 3185 Harrison Boulevard, Ogden, Utah 7-Eleven Store No. 27074 Explanation of Abbreviations DERR = Department of Environmental Response and Remediation MBTEXN = methyl tertiary-butyl ether, benzene, toluene, ethylbenzene, total xylenes, and naphthalene mg/L = milligrams per liter MTBE = methyl tertiary-butyl ether RPD = relative percent difference TPH-DRO = total petroleum hydrocarbons as diesel-range organics TPH-GRO = total petroleum hydrocarbons as gasoline-range organics UDEQ = Utah Department of Environmental Quality -- = no data <= analyte not detected above the specified laboratory reporting limit bold = analyte detected above the specified laboratory reporting limit bold = analytical result exceeds the specified UDEQ DERR Initial Screening Level bold = analytical result exceeds the specified UDEQ DERR Initial Screening Level and Tier 1 Screening Level * = For the original survey data, MW-6 was assigned an arbitrary TOC elevation of 100 feet, and the TOC elevations of the remaining wells were calculated according to that datum. All wells were re-surveyed on March 9, 2023, and MW-1 was assigned an arbitrary TOC elevation of 97.67 feet (which was the original calculated relative TOC elevation for MW-1). #= Wells were abandoned on April 8, 2022 to accommodate UTA construction along Harrison Boulevard. Replacement wells were installed on February 7 and 8, 2023. ~= The same analyte is found in the field blank. 1 = Laboratory method blank detected TPH-DRO for original analysis. Repeat analysis was completed outside of hold time. Repeat analysis result was higher than original. Repeat analysis result is reported in table. B = The same analyte is found in the associated blank. J2 = Surrogate recovery limits have been exceeded; values are outside lower control limits. J3 = The associated batch QC was outside the established quality control range for precision. J4 = The associated batch QC was outside the established quality control range for accuracy. J7 = Surrogate recovery cannot be used for control limit evaluation due to dilution. Q = Sample was prepared and/or analyzed past holding time as defined in the method. Concentrations should beconsidered minimum values. Z1 = The identification of the analyte is acceptable; the reported value is an estimate. Notes ▪March 24, 2022 samples were collected into 40 mL vials that contained 5 mL of methanol. Reported concentrations include a 40/35 dilution factor. ▪The first quarter 2023 groundwater monitoring and sampling event was conducted on March 9 and 10. All depth to water measurements were collected on March 9. ▪The second quarter 2023 groundwater monitoring and sampling event was conducted on June 6 and 7. All depth to water measurements were collected on June 6. ▪The third quarter 2023 groundwater monitoring and sampling event was conducted on September 13 and 14. All depth to water measurements were collected on September 13. ▪The second quarter 2024 groundwater monitoring and sampling event was conducted on June 26 and 27. All depth to water measurements were collected on June 26. ▪The fourth quarter 2024 groundwater monitoring and sampling event was conducted on December 11 and 12. All depth to water measurements were collected on December 11. fnl_dbs_27074_20241211-12.xlsx Water 3 of 3 Stantec Consulting Services Inc. GRAPHS GRAPH 1 MW-1 Select Concentration vs. Time Graphs 10 11 12 13 14 15 160.001 0.010 0.100 1.000 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 1A 7-Eleven Store No. 27074 MW-1 Benzene Concentration vs. Time ISL TSL Benzene Depth to Groundwater 10 11 12 13 14 15 160.01 0.10 1.00 10.00 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 1B 7-Eleven Store No. 27074 MW-1 Ethylebenzene Concentration vs. Time ISL TSL Ethylbenzene Depth to Groundwater 10 11 12 13 14 15 160.1 1.0 10.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Ja n - 2 3 Ma y - 2 3 Ju l - 2 3 Oc t - 2 3 Ja n - 2 4 Ap r - 2 4 Ju l - 2 4 Oc t - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 1C 7-Eleven Store No. 27074 MW-1 TPH-GRO Concentration vs. Time ISL TSL TPH-GRO Depth to Groundwater 10 11 12 13 14 15 160.1 1.0 10.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 1D 7-Eleven Store No. 27074 MW-1 TPH-DRO Concentration vs. Time ISL TSL TPH-DRO Depth to Groundwater GRAPH 2 MW-2/2R Select Concentration vs. Time Graphs 10 11 12 13 14 15 0.001 0.010 0.100 1.000 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 2A 7-Eleven Store No. 27074 MW-2/2R Benzene Concentration vs. Time ISL TSL Benzene Depth to Groundwater *Closed markers indicate MW-2R data. 10 11 12 13 14 15 0.1 1.0 10.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 2B 7-Eleven Store No. 27074 MW-2/2R Ethylebenzene Concentration vs. Time ISL TSL Ethylbenzene Depth to Groundwater *Closed markers indicate MW-2R data. 10 11 12 13 14 15 0.1 1.0 10.0 100.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Ja n - 2 3 Ma y - 2 3 Ju l - 2 3 Oc t - 2 3 Ja n - 2 4 Ap r - 2 4 Ju l - 2 4 Oc t - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 2C 7-Eleven Store No. 27074 MW-2/2R TPH-GRO Concentration vs. Time ISL TSL TPH-GRO Depth to Groundwater *Closed markers indicate MW-2R data. DUP-01 data used to plot 03/10/23 and 9/12/24 results. 10 11 12 13 14 15 0.1 1.0 10.0 100.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 2D 7-Eleven Store No. 27074 MW-2/2R TPH-DRO Concentration vs. Time ISL TSL TPH-DRO Depth to Groundwater *Closed markers indicate MW-2R data. GRAPH 3 MW-3 Select Concentration vs. Time Graphs 12 13 14 15 16 17 0.0001 0.0010 0.0100 0.1000 1.0000 Ju l - 2 0 Oc t - 2 0 Ja n - 2 1 Ap r - 2 1 Ju l - 2 1 Oc t - 2 1 Ja n - 2 2 Ap r - 2 2 Ju l - 2 2 Oc t - 2 2 Ja n - 2 3 Ap r - 2 3 Ju l - 2 3 Oc t - 2 3 Ja n - 2 4 Ap r - 2 4 Ju l - 2 4 Oc t - 2 4 De c - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 3A 7-Eleven Store No. 27074 MW-3 Benzene Concentration vs. Time ISL TSL Benzene Depth to Groundwater 12 13 14 15 16 17 0.1 1.0 10.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Ja n - 2 3 Ma y - 2 3 Ju l - 2 3 Oc t - 2 3 Ja n - 2 4 Ap r - 2 4 Ju l - 2 4 Oc t - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 3B 7-Eleven Store No. 27074 MW-3 TPH-GRO Concentration vs. Time ISL TSL TPH-GRO Depth to Groundwater 12 13 14 15 16 17 0.1 1.0 10.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 3C 7-Eleven Store No. 27074 MW-3 TPH-DRO Concentration vs. Time ISL TSL TPH-DRO Depth to Groundwater GRAPH 4 MW-5/5R Select Concentration vs. Time Graphs 10 11 12 13 14 15 16 170.1 1.0 10.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Ja n - 2 3 Ma y - 2 3 Ju l - 2 3 Oc t - 2 3 Ja n - 2 4 Ap r - 2 4 Ju l - 2 4 Oc t - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 4A 7-Eleven Store No. 27074 MW-5/5R TPH-GRO Concentration vs. Time ISL TSL TPH-GRO Depth to Groundwater *Closed markers indicate MW-5R data. 10 11 12 13 14 15 16 170.01 0.10 1.00 10.00 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Ja n - 2 3 Ma y - 2 3 Ju l - 2 3 Oc t - 2 3 Ja n - 2 4 Ap r - 2 4 Ju l - 2 4 Oc t - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 4A 7-Eleven Store No. 27074 MW-5/5R TPH-DRO Concentration vs. Time ISL TSL TPH-DRO Depth to Groundwater *Closed markers indicate MW-5R data. 11 12 13 14 15 160.1 1.0 10.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 5A 7-Eleven Store No. 27074 MW-7 TPH-GRO Concentration vs. Time ISL TSL TPH-GRO Depth to Groundwater 11 12 13 14 15 16 170.1 1.0 10.0 No v - 2 0 Fe b - 2 1 Ma y - 2 1 Au g - 2 1 No v - 2 1 Fe b - 2 2 Ma y - 2 2 Au g - 2 2 No v - 2 2 Fe b - 2 3 Ma y - 2 3 Au g - 2 3 No v - 2 3 Fe b - 2 4 Ma y - 2 4 Au g - 2 4 No v - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE GRAPH 5B 7-Eleven Store No. 27074 MW-7 TPH-DRO Concentration vs. Time ISL TSL TPH-DRO Depth to Groundwater GRAPH 5 MW-7 Select Concentration vs. Time Graphs 11 12 13 14 15 160.1 1.0 10.0 100.0 1,000.0 Ma r - 2 3 Ju n - 2 3 Se p - 2 3 De c - 2 3 Ma r - 2 4 Ju n - 2 4 Se p - 2 4 De c - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE ISL TSL TPH-DRO Depth to Groundwater GRAPH 6 7-Eleven Store No. 27074 MW-8 TPH-DRO Concentration vs. Time GRAPH 7 7-Eleven Store No. 27074 MW-9 TPH-DRO Concentration vs. Time 11 12 13 14 15 160.1 1.0 10.0 Ma r - 2 3 Ju n - 2 3 Se p - 2 3 De c - 2 3 Ma r - 2 4 Ju n - 2 4 Se p - 2 4 De c - 2 4 De p t h t o G r o u n d w a t e r ( f e e t ) Co n c e n t r a t i o n ( m g / L ) DATE ISL TSL TPH-DRO Depth to Groundwater ATTACHMENT 1 Laboratory Report and Chain-of-Custody Documentation ANALYTICAL REPORT December 26, 2024 711 Stantec - Salt Lake City, UT Sample Delivery Group:L1809483 Samples Received:12/13/2024 Project Number:203721870 Description:7-11 #27074 Ogden, UT Site:27074 Report To:Anna Skinner 2890 E Cottonwood Pkwy Suite 300 Salt Lake City, UT 84121 Entire Report Reviewed By: December 26, 2024 [Preliminary Report] Marty Edwards III Project Manager Results relate only to the items tested or calibrated and are reported as rounded values. This test report shall not be reproduced, except in full, without written approval of the laboratory. Where applicable, sampling conducted by Pace Analytical National is performed per guidance provided in laboratory standard operating procedures ENV-SOP-MTJL-0067 and ENV-SOP-MTJL-0068. Where sampling conducted by the customer, results relate to the accuracy of the information provided, and as the samples are received. Pace Analytical National 12065 Lebanon Rd Mount Juliet, TN 37122 615-758-5858 800-767-5859 mydata.pacelabs.com 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 1 of 22 December 26, 2024 Marty Edwards III Project Manager ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 1 of 22 TABLE OF CONTENTS Cp: Cover Page 1 Tc: Table of Contents 2 Ss: Sample Summary 3 Cn: Case Narrative 5 Sr: Sample Results 6 MW-1 L1809483-01 6 MW-2R L1809483-02 7 MW-3 L1809483-03 8 MW-5R L1809483-04 9 MW-7 L1809483-05 10 MW-8 L1809483-06 11 MW-9 L1809483-07 12 DUP-01 L1809483-08 13 TRIP BLANK L1809483-09 14 Qc: Quality Control Summary 15 Volatile Organic Compounds (GC) by Method 8015D/GRO 15 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 17 Semi-Volatile Organic Compounds (GC) by Method 8015D 19 Gl: Glossary of Terms 20 Al: Accreditations & Locations 21 Sc: Sample Chain of Custody 22 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 2 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 2 of 22 SAMPLE SUMMARY Collected by Collected date/time Received date/time MW-1 L1809483-01 GW Andrew Huffman 12/12/24 12:30 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC) by Method 8015D/GRO WG2422096 5 12/20/24 14:33 12/20/24 14:33 JBE Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2423378 50 12/22/24 02:52 12/22/24 02:52 JBE Mt. Juliet, TN Semi-Volatile Organic Compounds (GC) by Method 8015D WG2421585 1 12/19/24 08:11 12/19/24 21:54 TJD Mt. Juliet, TN Collected by Collected date/time Received date/time MW-2R L1809483-02 GW Andrew Huffman 12/12/24 12:00 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC) by Method 8015D/GRO WG2422096 1 12/20/24 14:12 12/20/24 14:12 JBE Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2424149 5 12/25/24 04:26 12/25/24 04:26 DWR Mt. Juliet, TN Semi-Volatile Organic Compounds (GC) by Method 8015D WG2421585 1 12/19/24 08:11 12/19/24 22:15 TJD Mt. Juliet, TN Collected by Collected date/time Received date/time MW-3 L1809483-03 GW Andrew Huffman 12/11/24 14:35 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC) by Method 8015D/GRO WG2421000 1 12/18/24 15:17 12/18/24 15:17 JAH Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2423378 1 12/21/24 23:08 12/21/24 23:08 JBE Mt. Juliet, TN Semi-Volatile Organic Compounds (GC) by Method 8015D WG2421585 1 12/19/24 08:11 12/19/24 22:35 TJD Mt. Juliet, TN Collected by Collected date/time Received date/time MW-5R L1809483-04 GW Andrew Huffman 12/11/24 15:35 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC) by Method 8015D/GRO WG2421000 1 12/18/24 15:40 12/18/24 15:40 JAH Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2423378 1 12/21/24 23:29 12/21/24 23:29 JBE Mt. Juliet, TN Semi-Volatile Organic Compounds (GC) by Method 8015D WG2421585 1 12/19/24 08:11 12/19/24 22:56 TJD Mt. Juliet, TN Collected by Collected date/time Received date/time MW-7 L1809483-05 GW Andrew Huffman 12/11/24 13:35 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC) by Method 8015D/GRO WG2421000 1 12/18/24 16:03 12/18/24 16:03 JAH Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2423378 1 12/21/24 23:49 12/21/24 23:49 JBE Mt. Juliet, TN Semi-Volatile Organic Compounds (GC) by Method 8015D WG2421585 1 12/19/24 08:11 12/19/24 23:17 TJD Mt. Juliet, TN Collected by Collected date/time Received date/time MW-8 L1809483-06 GW Andrew Huffman 12/12/24 11:00 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC) by Method 8015D/GRO WG2421000 1 12/18/24 16:26 12/18/24 16:26 JAH Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2423378 1 12/22/24 00:10 12/22/24 00:10 JBE Mt. Juliet, TN Semi-Volatile Organic Compounds (GC) by Method 8015D WG2421585 1 12/19/24 08:11 12/19/24 23:37 TJD Mt. Juliet, TN 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 3 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 3 of 22 SAMPLE SUMMARY Collected by Collected date/time Received date/time MW-9 L1809483-07 GW Andrew Huffman 12/12/24 10:05 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC) by Method 8015D/GRO WG2421000 1 12/18/24 16:49 12/18/24 16:49 JAH Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2423378 1 12/22/24 00:30 12/22/24 00:30 JBE Mt. Juliet, TN Semi-Volatile Organic Compounds (GC) by Method 8015D WG2421585 1 12/19/24 08:11 12/20/24 01:22 TJD Mt. Juliet, TN Collected by Collected date/time Received date/time DUP-01 L1809483-08 GW Andrew Huffman 12/12/24 00:00 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC) by Method 8015D/GRO WG2421000 1 12/18/24 17:12 12/18/24 17:12 JAH Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B WG2424149 25 12/25/24 04:47 12/25/24 04:47 DWR Mt. Juliet, TN Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2423378 1 12/22/24 00:50 12/22/24 00:50 JBE Mt. Juliet, TN Semi-Volatile Organic Compounds (GC) by Method 8015D WG2421585 1 12/19/24 08:11 12/20/24 01:42 TJD Mt. Juliet, TN Collected by Collected date/time Received date/time TRIP BLANK L1809483-09 GW Andrew Huffman 12/12/24 00:00 12/13/24 08:00 Method Batch Dilution Preparation Analysis Analyst Location date/time date/time Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 WG2423378 1 12/21/24 22:48 12/21/24 22:48 JBE Mt. Juliet, TN 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 4 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 4 of 22 CASE NARRATIVE All sample aliquots were received at the correct temperature, in the proper containers, with the appropriate preservatives, and within method specified holding times, unless qualified or notated within the report. Where applicable, all MDL (LOD) and RDL (LOQ) values reported for environmental samples have been corrected for the dilution factor used in the analysis. All Method and Batch Quality Control are within established criteria except where addressed in this case narrative, a non-conformance form or properly qualified within the sample results. By my digital signature below, I affirm to the best of my knowledge, all problems/anomalies observed by the laboratory as having the potential to affect the quality of the data have been identified by the laboratory, and no information or data have been knowingly withheld that would affect the quality of the data. [Preliminary Report] Marty Edwards III Project Manager Sample Delivery Group (SDG) Narrative pH outside of method requirement. Lab Sample ID Project Sample ID Method L1809483-03 MW-3 8015D L1809483-04 MW-5R 8015D 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 5 of 22 Marty Edwards III Project Manager ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 5 of 22 SAMPLE RESULTS - 01 L1809483 MW-1 Collected date/time: 12/12/24 12:30 Volatile Organic Compounds (GC) by Method 8015D/GRO Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) Low Fraction 2.74 0.500 5 12/20/2024 14:33 WG2422096 (S) a,a,a-Trifluorotoluene(FID)85.3 78.0-120 12/20/2024 14:33 WG2422096 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene 0.185 0.0500 50 12/22/2024 02:52 WG2423378 Toluene ND 0.0500 50 12/22/2024 02:52 WG2423378 Ethylbenzene 0.959 0.0500 50 12/22/2024 02:52 WG2423378 Xylenes, Total ND 0.150 50 12/22/2024 02:52 WG2423378 Methyl tert-butyl ether ND 0.00505 50 12/22/2024 02:52 WG2423378 Naphthalene 0.0516 Z1 0.0500 50 12/22/2024 02:52 WG2423378 (S) Toluene-d8 104 80.0-120 12/22/2024 02:52 WG2423378 (S) 4-Bromofluorobenzene 96.3 77.0-126 12/22/2024 02:52 WG2423378 (S) 1,2-Dichloroethane-d4 99.4 70.0-130 12/22/2024 02:52 WG2423378 Sample Narrative: L1809483-01 WG2423378: MTBE and Naphthalene were reported to the MDL. Semi-Volatile Organic Compounds (GC) by Method 8015D Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) High Fraction 4.07 0.100 1 12/19/2024 21:54 WG2421585 (S) o-Terphenyl 113 52.0-156 12/19/2024 21:54 WG2421585 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 6 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 6 of 22 SAMPLE RESULTS - 02 L1809483 MW-2R Collected date/time: 12/12/24 12:00 Volatile Organic Compounds (GC) by Method 8015D/GRO Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) Low Fraction 0.552 0.100 1 12/20/2024 14:12 WG2422096 (S) a,a,a-Trifluorotoluene(FID)85.8 78.0-120 12/20/2024 14:12 WG2422096 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene 0.00415 Z1 0.000471 5 12/25/2024 04:26 WG2424149 Toluene ND 0.00500 5 12/25/2024 04:26 WG2424149 Ethylbenzene 0.108 0.00500 5 12/25/2024 04:26 WG2424149 Xylenes, Total ND 0.0150 5 12/25/2024 04:26 WG2424149 Methyl tert-butyl ether ND 0.00500 5 12/25/2024 04:26 WG2424149 Naphthalene ND 0.0250 5 12/25/2024 04:26 WG2424149 (S) Toluene-d8 111 80.0-120 12/25/2024 04:26 WG2424149 (S) 4-Bromofluorobenzene 94.4 77.0-126 12/25/2024 04:26 WG2424149 (S) 1,2-Dichloroethane-d4 101 70.0-130 12/25/2024 04:26 WG2424149 Sample Narrative: L1809483-02 WG2424149: Dilution due to matrix. Benzene was reported to the MDL. Semi-Volatile Organic Compounds (GC) by Method 8015D Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) High Fraction 1.29 0.100 1 12/19/2024 22:15 WG2421585 (S) o-Terphenyl 98.9 52.0-156 12/19/2024 22:15 WG2421585 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 7 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 7 of 22 SAMPLE RESULTS - 03 L1809483 MW-3 Collected date/time: 12/11/24 14:35 Volatile Organic Compounds (GC) by Method 8015D/GRO Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) Low Fraction 0.349 0.100 1 12/18/2024 15:17 WG2421000 (S) a,a,a-Trifluorotoluene(FID)97.5 78.0-120 12/18/2024 15:17 WG2421000 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene ND 0.00100 1 12/21/2024 23:08 WG2423378 Toluene ND 0.00100 1 12/21/2024 23:08 WG2423378 Ethylbenzene ND 0.00100 1 12/21/2024 23:08 WG2423378 Xylenes, Total ND 0.00300 1 12/21/2024 23:08 WG2423378 Methyl tert-butyl ether ND 0.00100 1 12/21/2024 23:08 WG2423378 Naphthalene ND 0.00500 1 12/21/2024 23:08 WG2423378 (S) Toluene-d8 107 80.0-120 12/21/2024 23:08 WG2423378 (S) 4-Bromofluorobenzene 96.0 77.0-126 12/21/2024 23:08 WG2423378 (S) 1,2-Dichloroethane-d4 98.8 70.0-130 12/21/2024 23:08 WG2423378 Semi-Volatile Organic Compounds (GC) by Method 8015D Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) High Fraction 0.790 0.100 1 12/19/2024 22:35 WG2421585 (S) o-Terphenyl 98.4 52.0-156 12/19/2024 22:35 WG2421585 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 8 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 8 of 22 SAMPLE RESULTS - 04 L1809483 MW-5R Collected date/time: 12/11/24 15:35 Volatile Organic Compounds (GC) by Method 8015D/GRO Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) Low Fraction ND 0.100 1 12/18/2024 15:40 WG2421000 (S) a,a,a-Trifluorotoluene(FID)98.8 78.0-120 12/18/2024 15:40 WG2421000 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene ND 0.00100 1 12/21/2024 23:29 WG2423378 Toluene ND 0.00100 1 12/21/2024 23:29 WG2423378 Ethylbenzene ND 0.00100 1 12/21/2024 23:29 WG2423378 Xylenes, Total ND 0.00300 1 12/21/2024 23:29 WG2423378 Methyl tert-butyl ether ND 0.00100 1 12/21/2024 23:29 WG2423378 Naphthalene ND 0.00500 1 12/21/2024 23:29 WG2423378 (S) Toluene-d8 108 80.0-120 12/21/2024 23:29 WG2423378 (S) 4-Bromofluorobenzene 101 77.0-126 12/21/2024 23:29 WG2423378 (S) 1,2-Dichloroethane-d4 100 70.0-130 12/21/2024 23:29 WG2423378 Semi-Volatile Organic Compounds (GC) by Method 8015D Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) High Fraction 0.213 0.100 1 12/19/2024 22:56 WG2421585 (S) o-Terphenyl 98.9 52.0-156 12/19/2024 22:56 WG2421585 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 9 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 9 of 22 SAMPLE RESULTS - 05 L1809483 MW-7 Collected date/time: 12/11/24 13:35 Volatile Organic Compounds (GC) by Method 8015D/GRO Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) Low Fraction 0.384 0.100 1 12/18/2024 16:03 WG2421000 (S) a,a,a-Trifluorotoluene(FID)98.3 78.0-120 12/18/2024 16:03 WG2421000 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene ND 0.00100 1 12/21/2024 23:49 WG2423378 Toluene ND 0.00100 1 12/21/2024 23:49 WG2423378 Ethylbenzene ND 0.00100 1 12/21/2024 23:49 WG2423378 Xylenes, Total ND 0.00300 1 12/21/2024 23:49 WG2423378 Methyl tert-butyl ether ND 0.00100 1 12/21/2024 23:49 WG2423378 Naphthalene ND 0.00500 1 12/21/2024 23:49 WG2423378 (S) Toluene-d8 105 80.0-120 12/21/2024 23:49 WG2423378 (S) 4-Bromofluorobenzene 93.4 77.0-126 12/21/2024 23:49 WG2423378 (S) 1,2-Dichloroethane-d4 97.9 70.0-130 12/21/2024 23:49 WG2423378 Semi-Volatile Organic Compounds (GC) by Method 8015D Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) High Fraction 0.600 0.100 1 12/19/2024 23:17 WG2421585 (S) o-Terphenyl 108 52.0-156 12/19/2024 23:17 WG2421585 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 10 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 10 of 22 SAMPLE RESULTS - 06 L1809483 MW-8 Collected date/time: 12/12/24 11:00 Volatile Organic Compounds (GC) by Method 8015D/GRO Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) Low Fraction ND 0.100 1 12/18/2024 16:26 WG2421000 (S) a,a,a-Trifluorotoluene(FID)98.7 78.0-120 12/18/2024 16:26 WG2421000 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene ND 0.00100 1 12/22/2024 00:10 WG2423378 Toluene ND 0.00100 1 12/22/2024 00:10 WG2423378 Ethylbenzene ND 0.00100 1 12/22/2024 00:10 WG2423378 Xylenes, Total ND 0.00300 1 12/22/2024 00:10 WG2423378 Methyl tert-butyl ether ND 0.00100 1 12/22/2024 00:10 WG2423378 Naphthalene ND 0.00500 1 12/22/2024 00:10 WG2423378 (S) Toluene-d8 109 80.0-120 12/22/2024 00:10 WG2423378 (S) 4-Bromofluorobenzene 96.1 77.0-126 12/22/2024 00:10 WG2423378 (S) 1,2-Dichloroethane-d4 105 70.0-130 12/22/2024 00:10 WG2423378 Semi-Volatile Organic Compounds (GC) by Method 8015D Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) High Fraction 0.169 0.100 1 12/19/2024 23:37 WG2421585 (S) o-Terphenyl 94.7 52.0-156 12/19/2024 23:37 WG2421585 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 11 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 11 of 22 SAMPLE RESULTS - 07 L1809483 MW-9 Collected date/time: 12/12/24 10:05 Volatile Organic Compounds (GC) by Method 8015D/GRO Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) Low Fraction ND 0.100 1 12/18/2024 16:49 WG2421000 (S) a,a,a-Trifluorotoluene(FID)98.4 78.0-120 12/18/2024 16:49 WG2421000 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene ND 0.00100 1 12/22/2024 00:30 WG2423378 Toluene ND 0.00100 1 12/22/2024 00:30 WG2423378 Ethylbenzene ND 0.00100 1 12/22/2024 00:30 WG2423378 Xylenes, Total ND 0.00300 1 12/22/2024 00:30 WG2423378 Methyl tert-butyl ether ND 0.00100 1 12/22/2024 00:30 WG2423378 Naphthalene ND 0.00500 1 12/22/2024 00:30 WG2423378 (S) Toluene-d8 102 80.0-120 12/22/2024 00:30 WG2423378 (S) 4-Bromofluorobenzene 101 77.0-126 12/22/2024 00:30 WG2423378 (S) 1,2-Dichloroethane-d4 99.1 70.0-130 12/22/2024 00:30 WG2423378 Semi-Volatile Organic Compounds (GC) by Method 8015D Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) High Fraction 0.313 0.100 1 12/20/2024 01:22 WG2421585 (S) o-Terphenyl 86.3 52.0-156 12/20/2024 01:22 WG2421585 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 12 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 12 of 22 SAMPLE RESULTS - 08 L1809483 DUP-01 Collected date/time: 12/12/24 00:00 Volatile Organic Compounds (GC) by Method 8015D/GRO Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) Low Fraction 4.24 0.100 1 12/18/2024 17:12 WG2421000 (S) a,a,a-Trifluorotoluene(FID)102 78.0-120 12/18/2024 17:12 WG2421000 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene 0.158 0.00100 1 12/22/2024 00:50 WG2423378 Toluene 0.00140 0.00100 1 12/22/2024 00:50 WG2423378 Ethylbenzene 1.01 0.0250 25 12/25/2024 04:47 WG2424149 Xylenes, Total 0.0163 0.00300 1 12/22/2024 00:50 WG2423378 Methyl tert-butyl ether ND 0.00100 1 12/22/2024 00:50 WG2423378 Naphthalene 0.0456 0.00500 1 12/22/2024 00:50 WG2423378 (S) Toluene-d8 107 80.0-120 12/22/2024 00:50 WG2423378 (S) Toluene-d8 112 80.0-120 12/25/2024 04:47 WG2424149 (S) 4-Bromofluorobenzene 105 77.0-126 12/22/2024 00:50 WG2423378 (S) 4-Bromofluorobenzene 93.0 77.0-126 12/25/2024 04:47 WG2424149 (S) 1,2-Dichloroethane-d4 96.9 70.0-130 12/22/2024 00:50 WG2423378 (S) 1,2-Dichloroethane-d4 99.2 70.0-130 12/25/2024 04:47 WG2424149 Semi-Volatile Organic Compounds (GC) by Method 8015D Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time TPH (GC/FID) High Fraction 4.40 0.100 1 12/20/2024 01:42 WG2421585 (S) o-Terphenyl 114 52.0-156 12/20/2024 01:42 WG2421585 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 13 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 13 of 22 SAMPLE RESULTS - 09 L1809483 TRIP BLANK Collected date/time: 12/12/24 00:00 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 Result Qualifier RDL Dilution Analysis Batch Analyte mg/l mg/l date / time Benzene ND 0.00100 1 12/21/2024 22:48 WG2423378 Toluene ND 0.00100 1 12/21/2024 22:48 WG2423378 Ethylbenzene ND 0.00100 1 12/21/2024 22:48 WG2423378 Xylenes, Total ND 0.00300 1 12/21/2024 22:48 WG2423378 Methyl tert-butyl ether ND 0.00100 1 12/21/2024 22:48 WG2423378 Naphthalene ND 0.00500 1 12/21/2024 22:48 WG2423378 (S) Toluene-d8 108 80.0-120 12/21/2024 22:48 WG2423378 (S) 4-Bromofluorobenzene 102 77.0-126 12/21/2024 22:48 WG2423378 (S) 1,2-Dichloroethane-d4 102 70.0-130 12/21/2024 22:48 WG2423378 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 14 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 14 of 22 QUALITY CONTROL SUMMARYWG2421000 Volatile Organic Compounds (GC) by Method 8015D/GRO L1809483-03,04,05,06,07,08 Method Blank (MB) (MB) R4159879-3 12/18/24 12:37 MB Result MB Qualifier MB MDL MB RDL Analyte mg/l mg/l mg/l TPH (GC/FID) Low Fraction U 0.0314 0.100 (S) a,a,a-Trifluorotoluene(FID)99.3 78.0-120 Laboratory Control Sample (LCS) • Laboratory Control Sample Duplicate (LCSD) (LCS) R4159879-1 12/18/24 11:29 • (LCSD) R4159879-2 12/18/24 11:52 Spike Amount LCS Result LCSD Result LCS Rec.LCSD Rec.Rec. Limits LCS Qualifier LCSD Qualifier RPD RPD Limits Analyte mg/l mg/l mg/l %%%%% TPH (GC/FID) Low Fraction 5.00 5.22 5.56 104 111 72.0-127 6.31 20 (S) a,a,a-Trifluorotoluene(FID) 105 106 78.0-120 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 15 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 15 of 22 QUALITY CONTROL SUMMARYWG2422096 Volatile Organic Compounds (GC) by Method 8015D/GRO L1809483-01,02 Method Blank (MB) (MB) R4160990-2 12/20/24 12:42 MB Result MB Qualifier MB MDL MB RDL Analyte mg/l mg/l mg/l TPH (GC/FID) Low Fraction U 0.0314 0.100 (S) a,a,a-Trifluorotoluene(FID)86.4 78.0-120 Laboratory Control Sample (LCS) (LCS) R4160990-1 12/20/24 11:59 Spike Amount LCS Result LCS Rec.Rec. Limits LCS Qualifier Analyte mg/l mg/l %% TPH (GC/FID) Low Fraction 5.00 5.21 104 72.0-127 (S) a,a,a-Trifluorotoluene(FID) 93.0 78.0-120 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 16 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 16 of 22 QUALITY CONTROL SUMMARYWG2423378 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 L1809483-01,03,04,05,06,07,08,09 Method Blank (MB) (MB) R4161252-3 12/21/24 22:28 MB Result MB Qualifier MB MDL MB RDL Analyte mg/l mg/l mg/l Benzene U 0.0000941 0.00100 Toluene U 0.000278 0.00100 Ethylbenzene U 0.000137 0.00100 Xylenes, Total U 0.000174 0.00300 Methyl tert-butyl ether U 0.000101 0.00100 Naphthalene U 0.00100 0.00500 (S) Toluene-d8 112 80.0-120 (S) 4-Bromofluorobenzene 101 77.0-126 (S) 1,2-Dichloroethane-d4 103 70.0-130 Laboratory Control Sample (LCS) (LCS) R4161252-1 12/21/24 21:27 Spike Amount LCS Result LCS Rec.Rec. Limits LCS Qualifier Analyte mg/l mg/l %% Benzene 0.00500 0.00558 112 70.0-123 Toluene 0.00500 0.00494 98.8 79.0-120 Ethylbenzene 0.00500 0.00523 105 79.0-123 Xylenes, Total 0.0150 0.0149 99.3 79.0-123 Methyl tert-butyl ether 0.00500 0.00560 112 68.0-125 Naphthalene 0.00500 0.00336 67.2 54.0-135 (S) Toluene-d8 98.7 80.0-120 (S) 4-Bromofluorobenzene 89.1 77.0-126 (S) 1,2-Dichloroethane-d4 100 70.0-130 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 17 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 17 of 22 QUALITY CONTROL SUMMARYWG2424149 Volatile Organic Compounds (GC/MS) by Method 8260B/8260B/OA1 L1809483-02,08 Method Blank (MB) (MB) R4162028-5 12/24/24 23:32 MB Result MB Qualifier MB MDL MB RDL Analyte mg/l mg/l mg/l Benzene U 0.0000941 0.00100 Toluene U 0.000278 0.00100 Ethylbenzene U 0.000137 0.00100 Xylenes, Total U 0.000174 0.00300 Methyl tert-butyl ether U 0.000101 0.00100 Naphthalene U 0.00100 0.00500 (S) Toluene-d8 118 80.0-120 (S) 4-Bromofluorobenzene 97.0 77.0-126 (S) 1,2-Dichloroethane-d4 98.1 70.0-130 Laboratory Control Sample (LCS) (LCS) R4162028-1 12/24/24 21:47 Spike Amount LCS Result LCS Rec.Rec. Limits LCS Qualifier Analyte mg/l mg/l %% Benzene 0.00500 0.00496 99.2 70.0-123 Toluene 0.00500 0.00527 105 79.0-120 Ethylbenzene 0.00500 0.00514 103 79.0-123 Xylenes, Total 0.0150 0.0159 106 79.0-123 Methyl tert-butyl ether 0.00500 0.00499 99.8 68.0-125 Naphthalene 0.00500 0.00497 99.4 54.0-135 (S) Toluene-d8 110 80.0-120 (S) 4-Bromofluorobenzene 93.4 77.0-126 (S) 1,2-Dichloroethane-d4 99.8 70.0-130 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 18 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 18 of 22 QUALITY CONTROL SUMMARYWG2421585 Semi-Volatile Organic Compounds (GC) by Method 8015D L1809483-01,02,03,04,05,06,07,08 Method Blank (MB) (MB) R4160096-1 12/19/24 16:43 MB Result MB Qualifier MB MDL MB RDL Analyte mg/l mg/l mg/l TPH (GC/FID) High Fraction U 0.0605 0.100 (S) o-Terphenyl 96.5 52.0-156 Laboratory Control Sample (LCS) • Laboratory Control Sample Duplicate (LCSD) (LCS) R4160096-2 12/19/24 17:04 • (LCSD) R4160096-3 12/19/24 17:25 Spike Amount LCS Result LCSD Result LCS Rec.LCSD Rec.Rec. Limits LCS Qualifier LCSD Qualifier RPD RPD Limits Analyte mg/l mg/l mg/l %%%%% TPH (GC/FID) High Fraction 1.50 1.57 1.64 105 109 50.0-150 4.36 20 (S) o-Terphenyl 106 94.5 52.0-156 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 19 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 19 of 22 GLOSSARY OF TERMS Guide to Reading and Understanding Your Laboratory Report The information below is designed to better explain the various terms used in your report of analytical results from the Laboratory. This is not intended as a comprehensive explanation, and if you have additional questions please contact your project representative. Results Disclaimer - Information that may be provided by the customer, and contained within this report, include Permit Limits, Project Name, Sample ID, Sample Matrix, Sample Preservation, Field Blanks, Field Spikes, Field Duplicates, On-Site Data, Sampling Collection Dates/Times, and Sampling Location. Results relate to the accuracy of this information provided, and as the samples are received. Abbreviations and Definitions MDL Method Detection Limit. ND Not detected at the Reporting Limit (or MDL where applicable). RDL Reported Detection Limit. Rec.Recovery. RPD Relative Percent Difference. SDG Sample Delivery Group. (S) Surrogate (Surrogate Standard) - Analytes added to every blank, sample, Laboratory Control Sample/Duplicate and Matrix Spike/Duplicate; used to evaluate analytical efficiency by measuring recovery. Surrogates are not expected to be detected in all environmental media. U Not detected at the Reporting Limit (or MDL where applicable). Analyte The name of the particular compound or analysis performed. Some Analyses and Methods will have multiple analytes reported. Dilution If the sample matrix contains an interfering material, the sample preparation volume or weight values differ from the standard, or if concentrations of analytes in the sample are higher than the highest limit of concentration that the laboratory can accurately report, the sample may be diluted for analysis. If a value different than 1 is used in this field, the result reported has already been corrected for this factor. Limits These are the target % recovery ranges or % difference value that the laboratory has historically determined as normal for the method and analyte being reported. Successful QC Sample analysis will target all analytes recovered or duplicated within these ranges. Qualifier This column provides a letter and/or number designation that corresponds to additional information concerning the result reported. If a Qualifier is present, a definition per Qualifier is provided within the Glossary and Definitions page and potentially a discussion of possible implications of the Qualifier in the Case Narrative if applicable. Result The actual analytical final result (corrected for any sample specific characteristics) reported for your sample. If there was no measurable result returned for a specific analyte, the result in this column may state “ND” (Not Detected) or “BDL” (Below Detectable Levels). The information in the results column should always be accompanied by either an MDL (Method Detection Limit) or RDL (Reporting Detection Limit) that defines the lowest value that the laboratory could detect or report for this analyte. Uncertainty (Radiochemistry)Confidence level of 2 sigma. Case Narrative (Cn) A brief discussion about the included sample results, including a discussion of any non-conformances to protocol observed either at sample receipt by the laboratory from the field or during the analytical process. If present, there will be a section in the Case Narrative to discuss the meaning of any data qualifiers used in the report. Quality Control Summary (Qc) This section of the report includes the results of the laboratory quality control analyses required by procedure or analytical methods to assist in evaluating the validity of the results reported for your samples. These analyses are not being performed on your samples typically, but on laboratory generated material. Sample Chain of Custody (Sc) This is the document created in the field when your samples were initially collected. This is used to verify the time and date of collection, the person collecting the samples, and the analyses that the laboratory is requested to perform. This chain of custody also documents all persons (excluding commercial shippers) that have had control or possession of the samples from the time of collection until delivery to the laboratory for analysis. Sample Results (Sr) This section of your report will provide the results of all testing performed on your samples. These results are provided by sample ID and are separated by the analyses performed on each sample. The header line of each analysis section for each sample will provide the name and method number for the analysis reported. Sample Summary (Ss)This section of the Analytical Report defines the specific analyses performed for each sample ID, including the dates and times of preparation and/or analysis. Qualifier Description Z1 The identification of the analyte is acceptable; the reported value is an estimate. 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 20 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 20 of 22 Pace Analytical National 12065 Lebanon Rd Mount Juliet, TN 37122 Alabama 40660 Nebraska NE-OS-15-05 Alaska 17-026 Nevada TN000032021-1 Arizona AZ0612 New Hampshire 2975 Arkansas 88-0469 New Jersey–NELAP TN002 California 2932 New Mexico ¹TN00003 Colorado TN00003 New York 11742 Connecticut PH-0197 North Carolina Env375 Florida E87487 North Carolina ¹DW21704 Georgia NELAP North Carolina ³41 Georgia ¹923 North Dakota R-140 Idaho TN00003 Ohio–VAP CL0069 Illinois 200008 Oklahoma 9915 Indiana C-TN-01 Oregon TN200002 Iowa 364 Pennsylvania 68-02979 Kansas E-10277 Rhode Island LAO00356 Kentucky ¹ ⁶KY90010 South Carolina 84004002 Kentucky ²16 South Dakota n/a Louisiana AI30792 Tennessee ¹ ⁴2006 Louisiana LA018 Texas T104704245-20-18 Maine TN00003 Texas ⁵LAB0152 Maryland 324 Utah TN000032021-11 Massachusetts M-TN003 Vermont VT2006 Michigan 9958 Virginia 110033 Minnesota 047-999-395 Washington C847 Mississippi TN00003 West Virginia 233 Missouri 340 Wisconsin 998093910 Montana CERT0086 Wyoming A2LA A2LA – ISO 17025 1461.01 AIHA-LAP,LLC EMLAP 100789 A2LA – ISO 17025 ⁵1461.02 DOD 1461.01 Canada 1461.01 USDA P330-15-00234 EPA–Crypto TN00003 ACCREDITATIONS & LOCATIONS ¹ Drinking Water ² Underground Storage Tanks ³ Aquatic Toxicity ⁴ Chemical/Microbiological ⁵ Mold ⁶ Wastewater n/a Accreditation not applicable * Not all certifications held by the laboratory are applicable to the results reported in the attached report. * Accreditation is only applicable to the test methods specified on each scope of accreditation held by Pace Analytical. 1 Cp 2 Tc 3 Ss 4 Cn 5 Sr 6 Qc 7 Gl 8 Al 9 Sc ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:05 21 of 22 ACCOUNT:PROJECT:SDG:DATE/TIME:PAGE: 711 Stantec - Salt Lake City, UT 203721870 L1809483 12/26/24 18:11 21 of 22