Attachment_7_-_Colter_Bay_Landfill_Groundwater_Monitoring_Report_2024.pdf

COLTER BAY LANDFILL

2024 Annual Groundwater Monitoring Report

Grand Teton National Park

Prepared for the U.S. National Park Service

December 2024 i | P a g e

NATIONAL PARK SERVICE

Colter Bay Landfill

Grand Teton National Park

Prepared for: National Park Service

IMR Northern Rockies MABO

ATTN: Sharon L. LaRosa

P.O. Box 168 Mammoth Supply Center

22 Stable St.

Yellowstone NP, WY 82190

Prepared by: James Ben Osborn, Staff Scientist, Project Manager

Reviewed by: Scott Payne, PhD, P.G., Project Manager, Geologist, Hydrogeologist

Kevin Grabinski, PE, Environmental Department Manager

K:\Helena\GRAND TETON NATIONAL PARK\2024304 Grand Teton National Park Monitoring 2024\08Reports\2024 Colter Bay Landfill\GTNP_Colter Bay_ Annual Groundwater Monitoring Report_2024_Final.docx ii | P a g e

TABLE OF CONTENTS

1.0 Executive Summary

2.0 Introduction

3.0 Field Sampling and Analysis

3.1 Well Site Inspection

3.2 Monitoring Well Gauging

3.3 Monitoring Well Sampling

3.4 Laboratory Analysis

3.5 Quality Assurance and Quality Control Evaluation

3.6 Equipment Decontamination

3.7 Investigation Derived Waste

4.0 Data Presentation and Evaluation

4.1 Groundwater Flow

4.2 Analytical Results

5.0 Data Quality Review

6.0 Statistical Evaluation of Groundwater Data

7.0 Findings and Recommendations

8.0 References

LIST OF FIGURES

Figure 1 – Monitoring Well Locations

Figure 2 – Monitoring Well Potentiometric Surface

K:\Helena\GRAND TETON NATIONAL PARK\2024304 Grand Teton National Park Monitoring 2024\08Reports\2024 Colter Bay Landfill\GTNP_Colter Bay_ Annual Groundwater Monitoring Report_2024_Final.docx iii | P a g e

LIST OF TABLES

Table 1 – Groundwater Analytical Data Summary

Table 2-1 Summary of Onsite Wells

Table 3-1 Sampling Limits

Table 3-2 Sample Collection, Preservation and Handling Specifications

Table 3-3 QAQC Samples Collected

Table 4-1 2024 Water Quality Exceedances Colter Bay Landfill

Table 5-1. Summary of Primary and Duplicate Samples for Metals

LIST OF APPENDICES

Appendix A – Laboratory Report

Appendix B – Statistical Evaluation

Colter Bay Landfill, Grand Teton National Park

1 | P a g e

1.0 EXECUTIVE SUMMARY

The 2024 Annual Groundwater Monitoring Report is prepared by WWC Engineering (WWC) and summarizes the results of the groundwater monitoring effort conducted in 2024 on behalf of the National Park Service (NPS) at the Colter Bay landfill area in Grand Teton National Park (Park). Groundwater sampling activities were performed by WWC in September of 2024.

Approximately 18.3 miles northeast of Moose, Wyoming, the Colter Bay Landfill is accessible by vehicle on a gravel road north of Highway 191, southeast of the Colter Bay Village entrance.

The Landfill was historically used for the disposal of solid waste associated with park operations. In conjunction with the Wyoming Department of Environmental Quality (DEQ), the NPS has been conducting groundwater monitoring events to observe the conditions associated with the former landfill. To further characterizes the site, the installation of a groundwater monitoring well network has been established to provide periodic sampling of site wells for various parameters.

Groundwater and hydrogeologic conditions can vary significantly from year to year in the park.

Some of the landfill wells may exhibit higher or lower groundwater levels and these changes can modify the local hydrogeologic setting. Seasonal variation in groundwater level can be 15 to 25 feet lower compared to prior years and fluctuate between spring and fall. Groundwater flow direction is in a south-southeasterly direction.

Analytical testing identified 1,2- dibromoethane (EDB), beryllium, iron, lead, manganese, and Total Dissolved Solids in the groundwater at concentrations exceeding federal and state regulatory screening levels for drinking water. It should be noted that groundwater in the immediate site vicinity is not used as a source of drinking water, therefore, there are no eminent health risks posed by elevated concentrations at the site. No other analytical parameters were detected at concentrations above the regulatory screening levels. A statistical analysis was performed which confirmed that groundwater concentrations associated with the landfill exceed background conditions.

Based on the results of this assessment, WWC recommends continued monitoring of the landfill.

2 | P a g e

2.0 INTRODUCTION

WWC was contracted by the NPS to perform groundwater monitoring in accordance with purchase order number 140P1421P0072 at the Colter Bay landfill in Grant Teton National Park.

Groundwater sampling was performed in accordance with the Statement of Work outlined by the NPS. Prior to the September 2024 sampling, groundwater monitoring at the site was last performed in September 2022.

Field operations were conducted by WWC on September 19, 2024. The sampling effort consisted of collecting groundwater samples from the seven monitoring wells shown in Figure 1. WWC located and measured the static water level of all the onsite wells as summarized below in Table 2.1.

Table 2-1 Summary of Onsite Wells

Monitoring Well

TOC

Elevation

(ft AMSL1)

Static Water

Level

(ft BTOC2)

Total Depth

(ft BTOC)

Groundwater Elevation

(ft AMSL3)

MW-1 6,841.86 27.33 34.10 6,814.53

MW-2 6,849.69 44.92 88.4 6,804.77

MW-3 6,849.76 33.49 49.95 6,816.27

MW-4 6,841.89 28.71 38.31 6,813.18

MW-5 6,841.47 28.49 48.27 6,812.98

MW-6 6,845.17 32.11 43.21 6,813.06

MW-7 6,842.52 29.56 48.23 6,812.96

1 feet above mean sea level 2 feet below top of casing.

3 feet above mean sea level

• Current TOC Elevation for MW-3 unknown. Value shown is estimated based on TD measurements between 2019 and 2020

3 | P a g e

3.0 FIELD SAMPLING AND ANALYSIS

On September 19, 2024, WWC mobilized on site at the Colter Bay Landfill, performing groundwater sampling at seven monitoring wells. WWC executed a general site-wide inspection, detailing the site to identify any security concerns and comparing the site conditions from previous events. Sampling was performed in fair weather conditions, without any limiting factors.

3.1 WELL SITE INSPECTION

Monitoring wells onsite were visually inspected. Well site inspections were performed to note any significant issues which could potentially affect sampling integrity. Inspections included an evaluation of the condition of each well pad, protective housing, lock, casing, and well cap. All wells were in a suitable condition for monitoring.

3.2 MONITORING WELL GAUGING

Static Water Level measurements were taken from each well prior to sampling. A geo-slope indicator was used to measure the depth to groundwater from Top of Casing (TOC) to the nearest 0.01-ft. Measurements were taken from a designated mark on the well casing, or the north side of the casing to ensure continuity between monitoring events. Groundwater static water level and elevation measurements are presented in Section 2, Table 2.1.

3.3 MONITORING WELL SAMPLING

Low-flow sampling methods were implemented using a decontaminated Grundfos submersible variable frequency drive unit, ensuring only positive pressure in the system. Sampling was performed in accordance with Low Flow Sampling protocol in DEQ guidance DEQ-WMRD-GWM-

1. Each well was pumped at a rate that did not induce excessive drawdown. Samples were collected after field water quality parameters were stabilized (with a minimum of one casing well-volume) or after purging three well bore volumes. Field water quality and stabilization parameters were within the following limits:

Table 3-1 Sampling Limits

Parameter Stabilization Criteria

Temperature +/- 3%

Specific Conductance +/- 3% pH +/-0.1

Final stabilization parameters were documented in a designated field book. Concluding well purging, unfiltered samples were collected into properly labeled laboratory-provided sample containers. Samples were preserved on ice in coolers provided by the laboratory and shipped under proper chain-of-custody protocols to Energy Laboratories, Inc. (Helena, MT) for analysis of the requested analytes, per the scope of work.

4 | P a g e

3.4 LABORATORY ANALYSIS

Energy Laboratories is a U.S. EPA Region VIII certified drinking water laboratory and is accredited by the National Environmental Laboratory Accreditation Program (NELAP). All analyses were carried out in accordance with Wyoming Water Quality Rules and Regulations, Chapter 8, Section 7.

Groundwater samples were analyzed for WYDEQ Appendix A volatile organic compounds (VOC’s), Target Analyte List (TAL) Metals, and general groundwater chemistry parameters including alkalinity, ammonia, nitrate as N, chemical oxygen demand (COD), total cyanide, chloride, fluoride, sulfate, total organic carbon (TOC), total dissolved solids (TDS), and bicarbonate/carbonate alkalinity as CaCO3. The following table describes the sample collection, preservation, and handling specifications for this sampling event.

Table 3-2 Sample Collection, Preservation and Handling Specifications

Parameter Method Sample Matrix Preservation Container Type and Minimum Volume Holding Time

VOCs (Wyoming DEQ Appendix A List) SW8260B Water HCl 3-40 ml VOA 14 days

Target Analyte List (TAL) Metals

SW6010B

6020/EPA245.1

Water HNO3 1-120 ml Plastic

6020A

180 days 7470 (hg)

28 days

Total Dissolved Solids (TDS) A2540C Water Neat 1-250 ml Plastic 7days

Chemical Oxygen Demand (COD) EPA410.4 Water H2SO4 1-250 ml Amber 28 days

Cyanide Kelada-01 Water NaOH 1-1.250 ml Plastic 14 days

Ammonia EPA 350.1 Water H2SO4 1-250 ml Amber 28 days

Carbonate (CO3).

Bicarbonate

(HCO3)

A2320 B Water Neat 1-250 ml Plastic 14 days

Anions (Chloride, Fluoride, Sulfate, Nitrate) EPA300.0 Water Neat 1-250 ml Plastic

NO3:48

Hours; All Others, 28 days

Total Organic Carbon A5310 C Water H2SO4 1-250 ml Amber 28 days

5 | P a g e

3.5 QUALITY ASSURANCE AND QUALITY CONTROL EVALUATION

The following field Quality Assurance (QA) Quality Control (QC) samples were collected and analyzed by the laboratory as required by the Statement of Work.

Table 3-3 QAQC Samples Collected

Sample Type Purpose Frequency Notes

Trip Blank Evaluate potential for cross-contamination during sampling or transport

Two trip blanks were submitted for VOC analysis.

Two trip blanks were submitted for VOC analysis.

VOC results are discussed below, within Section 3.

Field Duplicate

Evaluate sampling and analytical precision

One field duplicate was submitted.

One field duplicate was submitted from well MW-1.

Field duplicate results are discussed within Section 5.

Matrix Spike Evaluate potential matrix effects on preparation and measurement methodology.

One MS/MSD per sample event

MS/MSD sample results are discussed within Section 5.

Two trip blanks were submitted to the laboratory for VOC analysis. Methylene Chloride was detected, below the reporting limit (RL), in the two trip blanks; however, it was not detected in the other samples submitted. Methylene Chloride is a common lab compound, and it is not uncommon to see lab related interference associated with this chemical. Acetone was also detected in the two trip blanks at concentrations greater than detected in the suite of samples.

Acetone is a common lab compound, and it is not uncommon to see lab related interference associated with the chemical. Cross-contamination is not suspected between samples during storage and shipping.

3.6 EQUIPMENT DECONTAMINATION

Dedicated sampling equipment was used when possible. Pre-cleaned and dedicated sampling materials/equipment were used to collect samples for laboratory analysis. After the samples were collected, dedicated equipment was placed respectively in labeled plastic bags for future use at the site. Non-disposable sampling equipment was decontaminated between each sampling location with a solution of de-ionized (DI) water and Liquinox detergent, followed by a DI water rise.

3.7 INVESTIGATION DERIVED WASTE

Investigation-derived waste (IDW) generated during this sampling event included purge water and decontamination fluids (i.e., liquid IDW), disposable sampling equipment and personal protection equipment.

WWC disposed of liquid IDW in accordance with the standards of the park wastewater administrator. Disposable sampling equipment and personal protective equipment was disposed of as municipal solid waste.

6 | P a g e

4.0 DATA PRESENTATION AND EVALUATION

The results of monitoring performed in September 2024 at the Colter Bay Landfill is presented in this section.

4.1 GROUNDWATER FLOW

Groundwater measurements collected by WWC in September 2024 have been used to prepare the potentiometric surface map provided as Figure 2.

Monitoring wells MW-1, MW-3, MW-4, MW-5, MW-6, and MW-7 all exhibited similar groundwater elevations based upon a comparison of the 2020, 2022, and 2024 groundwater elevation data.

Groundwater elevations in 2024 are higher than what was measured in 2022, returning to elevations close to what was measured in 2020. Historically, groundwater has maintained a south-southeasterly flow direction. The northeasterly direction flow direction reported in 2022 was the result of using an incorrect elevation for the top of casing elevation for MW-3 that was misreported in the 2020 report. Well MW-3 was used for contouring but should be noted that the top of casing (TOC) elevation for MW-3 has not been verified after repairs were completed to this monitoring well between the 2019 and 2020 assessments. It is recommended to conduct a survey as part of the next monitoring report to establish an accurate TOC elevation for MW-

3. MW-2 was excluded from contouring as it is screened in a deeper water-bearing zone than the other wells.

4.2 ANALYTICAL RESULTS

An analytical summary for the September 2024 Sampling Event is provided in Table 4-1 and includes all data with exceedances above Federal or State standards. Laboratory reports for all data and a sample ID key are provided in Appendix A.

Of the 87 analytes tested during the September 2024 sampling event, 1,2- dibromoethane (EDB), beryllium, iron, lead, manganese, and Total Dissolved Solids were detected at concentrations above quality standards for federal drinking and Wyoming groundwaters.

Federal and state regulatory standards and exceedances are summarized in Table 4-1. Wyoming Groundwater Protection Standards (GWPS) for Municipal Solid Waste Landfills are described in the August 17, 2022, Memorandum prepared by Kevin Frank (LRP) and Jody Weikart (SWP) of Wyoming DEQ.

Consistent with past data, EDB was detected in monitoring wells MW-4 and MW-5, which are located hydrologically down gradient from the landfill. In 2024, MW-6 had EDB present which, historically, was last detected in 2020. The highest levels of inorganic constituents continue to be detected in monitoring well MW-1.

Toluene, used as a gasoline additive and as an organic solvent, has historically been detected in low concentrations, in MW-1, MW-2, MW-4, MW-6, and MW-7; however, toluene was not detected in any of the wells in 2024.

7 | P a g e

Table 4-1 2024 Water Quality Exceedances Colter Bay Landfill

Constituent

WDEQ GW

Protection Standards

EPA MCL MW-1 MW-2 MW-3 MW-4 MW-5 MW-6 MW-7

1,2 Dibromoethane (µg/L) 0.05 *0.05 <1 <1 <1 0.85 1.2 0.75 <1

Beryllium (mg/L) 0.004 *0.004 0.005 <0.001 0.001 <0.001 <0.001 <0.001 <0.001

Iron (mg/L) **0.3 0.3 37.3 0.64 12.3 7.23 5.63 2.11 1.6

Lead (mg/L) **0.015 0.015 0.044 <0.001 0.02 0.005 0.004 0.002 0.001

Manganese (mg/L) 0.05 *0.05 4.43 0.057 5.09 0.187 0.141 0.103 0.053

Total Dissolved Solids (mg/L) 500 500 300 371 527 149 244 147 88

< Indicates chemical not detected above laboratory reporting limit

* EPA Secondary Maximum Contaminant Level (MCL)

** WY Class I Use Groundwater Protection Standard (GWPS) through SHWD

Bold red text indicates an exceedance of WY GPS and/or EPA MCL as noted.

5.0 DATA QUALITY REVIEW

All data generated as part of the September 2024 sampling event were subjected to rigorous data review consistent with U.S. EPA National Functional Guidelines for Inorganic Data Review, as summarized below:

Samples were analyzed for metals (except mercury) by Method SW6020 (Batch 74031 and 74088).

Holding Times: All samples were analyzed within the method specified holding time of 180 days.

Preservation: All samples were preserved in the field with nitric acid to achieve a pH < 2.

Samples were then placed in an iced cooler and shipped to specifications (≤ 6°C).

Method Blank: The purpose of the method blank is to evaluate the validity of the analytical results based on contamination resulting from field or laboratory activities. One method blank was analyzed for the sample batch.

Laboratory Control Sample: The purpose of a laboratory control sample (LCS) is to determine the validity of the analytical results based on the recovery of the digested LCS.

One LCS was collected for the sample batch. Percent recoveries ranged from 81% to 104%, within the method control limits of 80%-120%.

Duplicate Sample: The purpose of a duplicate sample is to evaluate laboratory precision.

One duplicate sample was collected from well MW-3. Five of the 23 analytes produced a

8 | P a g e relative percent difference (RPD) slightly above the acceptable limit. Cadmium, though not a chemical of interest at the Colter Bay site, was not within the RPD acceptable limit. MW- 3 exhibited higher turbidity when purging, likely influencing the difference in the inorganic and geochemical properties of the primary and secondary samples. Laboratory precision is not in question, high turbidity resulted in non-homogeneity in the field. A summary of the primary and duplicate samples and RPD calculations is provided in the table below.

Table 5-1. Summary of Primary and Duplicate Samples for Metals

Parameter (mg/L) MW-3 DUP RPD

Mercury (µg/L) 0.082 0.07 15.9%

Aluminum 16.9 14.1 18.1%

Antimony <0.001 <0.001 --

Arsenic 0.005 0.005 0%

Barium 0.59 0.47 22.6%

Beryllium <0.001 <0.001 --

Cadmium 0.003 0.002 40%

Calcium 21 20 4.9%

Chromium 0.012 0.011 8.7%

Cobalt 0.013 0.011 16.7%

Copper 0.033 0.028 16.4%

Iron 12.3 9.97 20.9%

Lead 0.02 0.016 22.2%

Magnesium 7 6 15.4%

Manganese 5.09 4.19 19.4%

Nickel 0.035 0.028 22.2%

Potassium 5 5 0%

Selenium 0.001 <0.001 --

Silver <0.001 <0.001 --

Sodium 155 152 2%

Thallium <0.005 <0.005 --

Vanadium 0.02 0.02 0%

Zinc 0.05 0.04 22.2%

9 | P a g e

Spike Sample Results: The purpose of spike sample analysis is to evaluate the effect of the sample matrix on the analytical results. One set of matrix spike (MS) and matrix spike duplicate (MSD) samples was analyzed for the sample batch. Matrix spike percent recoveries were within the method specified acceptance criteria of 75%-125%. The RPD between MS and MSD results were within method specified acceptance criteria (20%).

Samples were analyzed for mercury by EPA Method E245.1 (Batch 74047).

Holding Times: All samples were analyzed within the method-specified holding time of 28 days.

Preservation: All samples were preserved in the field with nitric acid to achieve a pH < 2.

Samples were then placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6ºC).

Method Blank: One method blank was analyzed for the sample batch. No analytes were present in the method blank.

Laboratory Control Sample: One LCS was collected for the sample batch. Percent recovery was 99%, within the method control limits of 90%-110%.

Spike Sample Results: Two sets of MS/MSD samples were analyzed for the sample batch.

Matrix spike percent recoveries were within the method specified acceptance criteria of 70%-130%. The RPD between MS and MSD results were within method specified acceptance criteria (20%).

Samples were analyzed for ammonia (as N) by EPA Method 350.1 (Batch R199118).

Holding Times: All samples were analyzed within the method-specified holding time of 28 days.

Preservation: All samples were preserved in the field with sulfuric acid to achieve a pH <

2. Samples were then placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6ºC).

Method Blank: One method blank was analyzed for the sample batch. No analytes were present in the method blank.

Laboratory Fortified Blank: One LFB was collected for the sample batch. Percent recovery was 101%, within the method control limits of 90%-110%.

Duplicate Sample: One duplicate sample was collected from MW-3. Nitrogen (as ammonia) was not detected at the reporting limit in the primary sample (<0.05 mg/L) or in the duplicate sample (<0.05 mg/L).

Spike Sample Results: Two sets of MS/MSD samples were analyzed for the sample batch.

Matrix spike percent recoveries were within the method specified acceptance criteria of 80%-120%. The RPD between MS and MSD results were within method specified acceptance criteria (10%).

10 | P a g e

Samples were analyzed for low level volatile organic compounds by SW8260B (Batch R198901).

Holding Times: All samples were analyzed within the method-specified holding time of 14 days.

Preservation: All samples were preserved in the field with hydrochloric acid to achieve a pH < 2. Samples were then placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6ºC).

Method Blank: One method blank was analyzed for the sample batch. No analytes were present in the method blank.

Laboratory Control Sample: One LCS was collected for the sample batch. Percent recovery range was within the method control limits for each specific analyte.

Duplicate Sample: One duplicate sample was collected from MW-3. Acetone was detected in the duplicate (7.3 µg/L) and primary (8.7 µg/L) samples.

Samples were analyzed for cyanide by Kelada-01 (Batch B_429513).

Holding Times: All samples were analyzed within the method-specified holding time of 14 days.

Preservation: All samples were preserved in the field with sodium hydroxide. Samples were then placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6ºC).

Method Blank: One method blank was analyzed for each sample batch. No analytes were present in the method blank.

Laboratory Fortified Blank: One LFB was collected for the sample batch. Percent recovery was 100%, within the method control limits of 90%-110%.

Laboratory Control Sample: One LCS was collected for the sample batch. Percent recovery was 105%, within the method control limits of 90%- 110%.

Spike Sample Results: One set of MS/MSD samples was analyzed for each sample batch.

The MS/MSD matrix spike percent recoveries were within the method specified acceptance criteria of 90%-110%. The RPD between MS and MSD results were within method specified acceptance criteria (20%).

Samples were analyzed for chemical oxygen demand by EPA Method 410.4 (Batch 74201).

Holding Times: All samples were analyzed within the method-specified holding time of 28 days.

Preservation: All samples were preserved in the field with sulfuric acid to achieve a pH <

2. Samples were then placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6°C).

11 | P a g e

Method Blank: One method blank was analyzed for the sample batch. No analytes were present in the method blank.

Laboratory Control Sample: One LCS was collected for the sample batch. Percent recovery was 106%, within the method control limits of 90%-110%.

Spike Sample Results: Two sets of MS/MSD samples were analyzed for the sample batch.

Matrix spike percent recoveries were within the method specified acceptance criteria of 90%-110%. The RPD between MS and MSD results were within method specified acceptance criteria (20%).

Samples were analyzed for anions by EPA Method 300.0 (Batch R198979 and R199079).

Holding Times: All samples were analyzed within the method-specified holding time of 48 hours for nitrate and 28 days for all other parameters.

Preservation: Samples were collected into laboratory-provided neat containers and placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6°C).

Method Blank: One method blank was analyzed each sample batch. No analytes were present in the method blank.

Laboratory Fortified Blank: One LFB was collected for each sample batch. Percent recovery ranged from 91%-100%. All RPDs were within the method control limits of 90%-110%.

Spike Sample Results: Six sets of MS/MSD samples were analyzed for the sample batch.

Matrix spike percent recoveries were within the method specified acceptance criteria of 90%-100%, with the exception of sulfate (87%) for the fifth MSD. The RPD between MS and MSD results were within method specified acceptance criteria (20%).

Duplicate Sample: One duplicate sample was collected from well MW-3. A summary of the primary and duplicate samples and relative percent difference calculations is provided in the table below. All RPDs were within acceptable limits.

Parameter (mg/L) MW-1 DUP RPD

Chloride 165 164 0.6%

Fluoride <0.1 <0.1 -

Sulfate 14 13 7.4%

12 | P a g e

Samples were analyzed for total organic carbon by A5310C (Batch B_R430222).

Holding Times: All samples were analyzed within the method-specified holding time of 28 days.

Preservation: All samples were preserved in the field with sulfuric acid to achieve a pH <

2. Samples were then placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6°C).

Method Blank: One method blank was analyzed for the sample batch. No analytes were present in the method blank.

Laboratory Control Sample: One LCS was collected for the sample batch. Percent recovery was 101%, within the method control limits of 91%-111%.

Duplicate Sample: One duplicate sample was collected from MW-3 as shown in the table below. The RPD for the primary and duplicate sample were within acceptance criteria (20%).

Parameter (mg/L) MW-3 DUP RPD

Organic Carbon, Total 13 12 8%

Spike Sample Results: Three set of MS/MSD samples were analyzed for the sample batch.

Matrix spike percent recoveries were within the method specified acceptance criteria of 91%-111%.

Samples were analyzed for alkalinity by A2320B (Batch R198750 and R199082).

Holding Times: All samples were analyzed within the method-specified holding time of 14 days.

Preservation: All samples were placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6°C).

Method Blank: One method blank was analyzed for the sample batch. No analytes were present in the method blank.

Laboratory Control Sample: One LCS was collected for the sample batch. Percent recovery was 100%, within the method control limits of 90%-110%. LCS RPD was within acceptance criteria.

Duplicate Sample: One duplicate sample was collected from MW-3. A summary of the primary and duplicate samples and relative percent difference calculations are provided in the table below. All RPDs were within acceptable limits.

13 | P a g e

Alkalinity, Bicarbonate 170 170 0%

Alkalinity, Carbonate <4.00 <4.00 -

Alkalinity, Total 140 140 0%

Lab Duplicate Results: Two duplicates were analyzed for the sample batch. The duplicates were well within the method specified acceptance criteria (10%).

Samples were analyzed for total dissolved solids by A2540C (Batch TDS02240920A).

Holding Times: All samples were analyzed within the method-specified holding time of 7 days.

Preservation: Samples were collected into laboratory-provided neat containers and placed in an iced cooler and shipped to the laboratory. The cooler was received at the laboratory within temperature specifications (≤ 6°C).

Method Blank: One method blanks was analyzed for the sample batch. No analytes were present in the method blank.

Laboratory Control Sample: One LCS was collected for the sample batch. Percent recovery was 99%, within the method control limits of 90%-110%.

Duplicate Sample: One duplicate sample was collected from MW-3 as shown in the table below. The RPD was within the acceptable limit.

Total Dissolved Solids 527 553 4.8%

Lab Duplicate Results: One lab duplicate was analyzed for the sample batch. The duplicate produced a result within method specified acceptance criteria (10%).

14 | P a g e

6.0 STATISTICAL EVALUATION OF GROUNDWATER DATA

An analysis of Colter Bay groundwater data set from September 2006 through September 2024 was performed using EPA’s ProUCL ver. 5.1 statistical software package (EPA, 2015) to evaluate the data in accordance with Chapter 2 of the WYDEQ Solid Waste Rules and Regulations. A nonparametric hypothesis testing of medians was used to evaluate the groundwater data set for elevated chemical concentrations. The statistical summary and ProUCL output are provided in Appendix B.

Initially, a one-way analysis of variance test for each analyte, Kruskal-Wallis, to determine which parameters indicated a statistical difference in the population (i.e., between the background (MW-2 and MW-3) and downgradient (MW-1, MW-4, MW-5, MW-6, and MW-7) datasets). As shown in the summary table in Appendix B, this test identified 3 parameters for which there was a statistical difference in the medians of the populations.

• The following parameters did not exhibit a difference between background and downgradient data sets: 1,2 dichloroethane, toluene, iron, and lead.

• The following parameters exhibited a difference between background and downgradient data sets: 1,2-dibromoethane, barium, and manganese.

For these 3 parameters, a comparison of the medians of each downgradient well to each background well was made to determine where potentially significant exceedances were possible. If the median concentration in any well exceeded the median concentration in either background well, a one-sided Gehan test was performed against each background well to evaluate the null hypothesis that downgradient concentrations were less than or equal to the background concentrations. Those comparisons (with p-values less than 0.05, indicating that the null hypothesis is rejected) indicated that site concentrations are elevated compared to background concentrations.

• Groundwater samples from downgradient wells did not exceed background concentrations for 1,2 dichloroethane, iron, lead, and manganese.

• 1,2-dibromoethane concentrations in groundwater samples from MW-4 and MW- 5 exceed background concentrations in MW-2 and MW-3.

• Barium concentrations in groundwater samples from MW-1 exceed the background concentrations in MW-2. MW-5 exceeded the background concentrations in MW-2.

15 | P a g e

7.0 FINDINGS AND RECOMMENDATIONS

The 2024 sample results support the following findings:

• Continued fluctuations were observed in groundwater elevation data compared to previous monitoring events. The groundwater elevations from 2020 through 2024 are lower than groundwater elevations taken in 2012 and 2019; however, the groundwater elevations were assessed in July of 2012 and June of 2019, while the 2020, 2022, and 2024 groundwater elevations were assessed in September in each of those years.

• Groundwater flow at the time of sampling is in a south-southeasterly direction. This flow direction is consistent with the historically reported flow direction.

• Most analytical parameters were either not detected or were not detected at concentrations exceeding applicable water quality standards.

• 1,2-dibromoethane, beryllium, iron, lead, manganese, and TDS were detected in groundwater samples at the Colter Bay Landfill at concentrations above EPA MCLs/SMCLs and corresponding Wyoming DEQ groundwater protection standards for domestic use. Based on available records, contaminated groundwater is not used as a source of drinking water in the vicinity of the Colter Bay Landfill.

• Statistical evaluation of the site data confirms that downgradient monitoring wells contain higher levels of certain constituents than background monitoring wells.

Based on the results of this assessment, WWC recommends continuing monitoring the Colter Bay Landfill site.

16 | P a g e

8.0 REFERENCES

EPA, (1996). Low-Flow (Minimal Drawdown) Groundwater Sampling Procedure (PDF). U.S.

Environmental Protection Agency, April.

EPA, 2015, ProUCL Software ver. 5.1.002, developed by Lockheed Martin on behalf of U.S.

Environmental Protection Agency.

EPA, (2017). Low Stress (low flow) Purging and Sampling Procedure for the Collection of Groundwater Samples from Monitoring Wells (pdf). U.S. Environmental Protection Agency, Revised September 19.

PPB, 2020, Colter Bay Landfill Groundwater Monitoring Report, prepared by PPB Enviro- Solutions on behalf of the National Park Service, October.

Wood, 2019, Grant Teton National Park Colter Bay Landfill Groundwater Monitoring Report, prepared by Wood Environment & Infrastructure Solutions, Inc. on behalf of the National Park Service, December.

WWC, 2022, Colter Bay Landfill Annual Groundwater Monitoring Report Grand Teton National Park, prepared by WWC Engineering on behalf of the National Park Service, December.

FIGURES

TABLE 1

Table 1. Groundwater Analytical Summary

Analyte

WYDEQ

Screening Level

MW-1 MW-2 MW-3 MW-4 MW-5 MW-6 MW-7

1,2-Dibromoethane *0.05 <1 <1 <1 0.85 1.2 0.75 <1 Xylenes (Total) *10 <1 <1 <1 <1 <1 <1 <1 Toluene 1000 <1 <1 <1 <1 <1 <1 <1

Mercury (µg/L) 2 0.136 <0.005 0.082 0.013 0.064 0.009 <0.005 Aluminum NE 55.7 0.32 16.9 8.19 7.08 2.19 1.35 Antimony 0.006 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Arsenic 0.05 0.008 0.001 0.005 0.001 0.001 <0.001 <0.001 Barium 2 1 0.13 0.59 0.15 0.29 0.11 0.06 Beryllium *0.004 0.005 <0.001 0.001 <0.001 <0.001 <0.001 <0.001 Cadmium 0.005 0.002 <0.001 0.003 <0.001 <0.001 <0.001 <0.001 Calcium NE 86 47 21 23 36 20 11 Chromium 0.1 0.032 <0.005 0.012 0.009 0.007 <0.005 <0.005 Cobalt NE 0.019 <0.005 0.013 <0.005 <0.005 <0.005 <0.005 Copper 1 0.06 <0.005 0.033 0.011 0.009 <0.005 <0.005 Iron 0.3 37.3 0.64 12.3 7.23 5.63 2.11 1.6 Lead 0.015 0.044 <0.001 0.02 0.005 0.004 0.002 0.001 Magnesium NE 23 11 7 5 8 4 3 Manganese 0.05 4.43 0.057 5.09 0.187 0.141 0.103 0.053 Nickle NE 0.048 <0.005 0.035 0.01 <0.005 <0.005 <0.005 Potassium NE 16 4 5 3 8 2 2 Selenium 0.05 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Silver 0.1 <0.001 <0.001 0.001 <0.001 <0.001 <0.001 <0.001 Sodium NE 10 37 155 11 15 8 5 Thallium *0.002 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 Vanadium NE 0.05 <0.01 0.02 0.01 <0.01 <0.01 <0.01 Zinc 5 0.2 0.02 0.05 0.02 0.02 0.03 0.01

Chloride 250 2 115 164 38 40 35 10 Nitrogen, Nitrate (As N) 10 0.77 0.65 0.99 0.96 0.8 0.93 0.36 Sulfate 250 12 6 14 3 8 2 2 Bicarbonate (As HCO3) NE 280 97 170 46 120 36 37 Alkalinity, Total (As CaCO3) NE 230 80 140 38 98 30 31 Chemical Oxygen Demand NE 35 11 64 <5 <5 6 6 Nitrogen, Ammonia (As N) 0.5 <.05 <.05 <.05 <.05 <.05 <.05 <.05 Total Dissolved Solids 500 300 371 527 149 244 147 88 Organic Carbon, Total NE 4 2 13 <2 3 <2 <2

* National Primary Drinking Water Screening Level (EPA MCLs)

Volatile Organic Compounds (µg/L)

TAL Metals Total (mg/L)

General Water Chemistry Parameters (mg/L)

APPENDIX A

Laboratory Report

Well Lab Sample ID Field Sample ID

Field Blank H24090718-001 0919-CBL-101

MW-3 H24090718-002 0919-CBL-102

MW-3 (Duplicate) H24090718-003 0919-CBL-103

MW-2 H24090718-004 0919-CBL-104

MW-6 H24090718-005 0919-CBL-105

MW-7 H24090718-006 0919-CBL-106

MW-4 H24090718-007 0919-CBL-107

MW-5 H24090718-008 0919-CBL-108

MW-1 H24090718-009 0919-CBL-109

H24090718-010 Trip Blank 1 H24090718-011 Trip Blank 2

Colter Bay Landfill Sample ID Key 2024

ANALYTICAL SUMMARY REPORT

The analyses presented in this report were performed by Energy Laboratories, Inc., 3161 E. Lyndale Ave., Helena, MT 59604, unless otherwise noted. Any exceptions or problems with the analyses are noted in the report package. Any issues encountered during sample receipt are documented in the Work Order Receipt Checklist.

The results as reported relate only to the item(s) submitted for testing. This report shall be used or copied only in its entirety. Energy Laboratories, Inc. is not responsible for the consequences arising from the use of a partial report.

Energy Laboratories, Inc. verifies the reported results for the analysis has been technically reviewed and approved for release.

If you have any questions regarding these test results, please contact your Project Manager.

Lab ID Client Sample ID Collect Date Receive Date Matrix Test

H24090718-001 0919-CBL-101 09/19/24 7:00 09/20/24 Aqueous Metals by ICP/ICPMS, Total Alkalinity to pH 4.5 Cyanide, Total Manual Distillation Chemical Oxygen Demand Carbon, Total Organic Mercury, Total Anions by Ion Chromatography Nitrogen, Ammonia Nitrogen, Nitrite Nitrogen, Nitrate + Nitrite Nitrogen, Nitrate Metals Digestion by SW3010A Preparation for COD testing HACH Mercury Digestion by E245.1 Solids, Total Dissolved 8260-Volatile Organic Comp, 40 CFR Part 258 App I

H24090718-002 0919-CBL-102 09/19/24 8:00 09/20/24 Aqueous Same As Above

H24090718-003 0919-CBL-103 09/19/24 9:00 09/20/24 Aqueous Same As Above

H24090718-004 0919-CBL-104 09/19/24 10:00 09/20/24 Aqueous Same As Above

H24090718-005 0919-CBL-105 09/19/24 11:00 09/20/24 Aqueous Same As Above

H24090718-006 0919-CBL-106 09/19/24 12:00 09/20/24 Aqueous Same As Above

H24090718-007 0919-CBL-107 09/19/24 13:00 09/20/24 Aqueous Same As Above

H24090718-008 0919-CBL-108 09/19/24 14:00 09/20/24 Aqueous Same As Above

H24090718-009 0919-CBL-109 09/19/24 15:00 09/20/24 Aqueous Same As Above

H24090718-010 Trip Blank 1 09/19/24 7:00 09/20/24 Trip Blank 8260-Volatile Organic Comp, 40 CFR Part 258 App I

H24090718-011 Trip Blank 2 09/19/24 11:00 09/20/24 Trip Blank Same As Above

Kirk Eng.and Natural Rsrcs Inc

Project Name: GTNP COLTER BAY LANDFILL

Work Order: H24090718

PO Box 636

Sheridan, MT 59749-0636

October 10, 2024

H2205Quote ID:

Energy Laboratories Inc Helena MT received the following 11 samples for Kirk Eng.and Natural Rsrcs Inc on 9/20/2024 for analysis.

Project: GTNP COLTER BAY LANDFILL

CLIENT: Kirk Eng.and Natural Rsrcs Inc

Work Order: H24090718 CASE NARRATIVE

10/10/24Report Date:

Tests associated with analyst identified as ELI-B were subcontracted to Energy Laboratories, 1120 S. 27th St., Billings, MT, EPA Number MT00005.

LABORATORY ANALYTICAL REPORT

Client: Kirk Eng.and Natural Rsrcs Inc

Project: GTNP COLTER BAY LANDFILL

Lab ID: H24090718-001

Client Sample ID: 0919-CBL-101 Collection Date: 09/19/24 07:00

Matrix: Aqueous Report Date: 10/10/24

DateReceived: 09/20/24

Prepared by Helena, MT Branch

Analyses Result Units Analysis Date / ByRL MethodMCLQUAL Prep Date Prep Method RunID

Run

Order BatchID

PHYSICAL PROPERTIES

L 09/20/24 14:29 / SRW20mg/LNDSolids, Total Dissolved TDS @ 180 C A2540 C Sartorius-BCA124-1S_240920B : 21 TDS20240920A

TDS did not obtain the minimum residue requirement of 2.5 mg residue.

INORGANICS

09/23/24 19:53 / eer4mg/LNDAlkalinity, Total as CaCO3 A2320 B PHSC_101-H_240923A : 120 R198750

09/23/24 19:53 / eer4mg/LNDBicarbonate as HCO3 A2320 B PHSC_101-H_240923A : 120 R198750

09/23/24 19:53 / eer4mg/LNDCarbonate as CO3 A2320 B PHSC_101-H_240923A : 120 R198750

10/02/24 20:21 / eer1mg/LNDChloride E300.0 IC METROHM_241001A : 122 R199079

10/02/24 20:21 / eer1mg/LNDSulfate E300.0 IC METROHM_241001A : 122 R199079

10/02/24 20:21 / eer0.1mg/LNDFluoride E300.04 IC METROHM_241001A : 122 R199079

09/25/24 16:59 / eli-b0.005mg/LNDCyanide, Total Kelada-01 SUB-B429513 : 55 B_R429513

AGGREGATE ORGANICS

10/08/24 02:23 / eli-b2mg/LNDOrganic Carbon, Total (TOC) A5310 C SUB-B430222 : 12 B_R430222

09/30/24 18:11 / eer5mg/LNDOxygen Demand, Chemical (COD) E410.4 09/30/24 10:30 HACH 800 GENESYS 20_240930B : 5 74201

NUTRIENTS

10/02/24 15:20 / JAR0.05mg/LNDNitrogen, Ammonia as N E350.1 FIA203-HE_241002A : 163 R199118

10/10/24 16:06 / JCS0.01mg/LNDNitrogen, Nitrate as N E353.2 CALC_241010C : 1 241010_INORG

10/01/24 12:24 / JAR0.01mg/LNDNitrogen, Nitrate+Nitrite as N E353.2 SEAL AA500_241001A : 186 R199083

09/20/24 12:05 / JAR0.01mg/LNDNitrogen, Nitrite as N E353.2 FIA203-HE_240920C : 30 R198769

METALS, TOTAL

09/24/24 12:03 / kjb0.005ug/LNDMercury E245.1 09/23/24 13:03 E245.1 HGCV205-H_240924B : 19 74047

METALS, TOTAL

10/09/24 11:18 / dck0.03mg/LNDAluminum SW6020 09/23/24 07:55 SW3010A ICPMS205-H_241008B : 150 74031

09/25/24 23:35 / dck0.001mg/LNDAntimony SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240925A : 158 74031

09/26/24 18:06 / dck0.001mg/LNDArsenic SW6020 09/23/24 07:55 SW3010A ICPMS205-H_240926B : 25 74031

09/25/24 23:35 / dck0.05mg/LNDBarium SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240925A : 158 74031

09/25/24 23:35 / dck0.001mg/LNDBeryllium SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240925A : 158 74031

09/25/24 23:35 / dck0.001mg/LNDCadmium SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240925A : 158 74031

09/25/24 00:32 / slj1mg/LNDCalcium SW6010B 09/23/24 07:55 SW3010A ICP2-HE_240924A : 173 74031

09/25/24 23:35 / dck0.005mg/LNDChromium SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240925A : 158 74031

09/26/24 18:06 / dck0.005mg/LNDCobalt SW6020 09/23/24 07:55 SW3010A ICPMS205-H_240926B : 25 74031

09/26/24 18:06 / dck0.005mg/LNDCopper SW6020 09/23/24 07:55 SW3010A ICPMS205-H_240926B : 25 74031

Report

Definitions:

RL - Analyte Reporting Limit MCL - Maximum Contaminant Level

QCL - Quality Control Limit ND - Not detected at the Reporting Limit (RL)

L -Lowest available reporting limit for the analytical method used and/or volume submitted Page 3 of 116

Project: GTNP COLTER BAY LANDFILL

Lab ID: H24090718-001

Client Sample ID: 0919-CBL-101 Collection Date: 09/19/24 07:00

Matrix: Aqueous Report Date: 10/10/24

DateReceived: 09/20/24

Prepared by Helena, MT Branch

Analyses Result Units Analysis Date / ByRL MethodMCLQUAL Prep Date Prep Method RunID

Run

Order BatchID

METALS, TOTAL

09/27/24 20:45 / dck0.03mg/LNDIron SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240927A : 136 74031

09/25/24 23:35 / dck0.001mg/LNDLead SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240925A : 158 74031

09/25/24 00:32 / slj1mg/LNDMagnesium SW6010B 09/23/24 07:55 SW3010A ICP2-HE_240924A : 173 74031

09/27/24 20:45 / dck0.001mg/LNDManganese SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240927A : 136 74031

09/26/24 18:06 / dck0.005mg/LNDNickel SW6020 09/23/24 07:55 SW3010A ICPMS205-H_240926B : 25 74031

09/25/24 00:32 / slj1mg/LNDPotassium SW6010B 09/23/24 07:55 SW3010A ICP2-HE_240924A : 173 74031

09/26/24 18:06 / dck0.001mg/LNDSelenium SW6020 09/23/24 07:55 SW3010A ICPMS205-H_240926B : 25 74031

09/25/24 23:35 / dck0.001mg/LNDSilver SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240925A : 158 74031

09/25/24 00:32 / slj1mg/LNDSodium SW6010B 09/23/24 07:55 SW3010A ICP2-HE_240924A : 173 74031

09/25/24 23:35 / dck0.005mg/LNDThallium SW6020 09/23/24 07:55 SW3010A ICPMS206-H_240925A : 158 74031

09/26/24 18:06 / dck0.01mg/LNDVanadium SW6020 09/23/24 07:55 SW3010A ICPMS205-H_240926B : 25 74031

09/26/24 18:06 / dck0.01mg/LNDZinc SW6020 09/23/24 07:55 SW3010A ICPMS205-H_240926B : 25 74031

VOLATILE ORGANIC COMPOUNDS

JT 09/26/24 13:55 / kmh20ug/L4.5Acetone SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh20ug/LNDAcrylonitrile SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDBenzene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDBromochloromethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDBromodichloromethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDBromoform SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDBromomethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDCarbon disulfide SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDCarbon tetrachloride SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDChlorobenzene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDChlorodibromomethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDChloroethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDChloroform SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDChloromethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,2-Dibromo-3-chloropropane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,2-Dibromoethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDDibromomethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,2-Dichlorobenzene SW8260B 5973MSD_240926A : 8 R198901

Report

Definitions:

RL - Analyte Reporting Limit MCL - Maximum Contaminant Level

QCL - Quality Control Limit ND - Not detected at the Reporting Limit (RL)

T - Analyte detected in the associated trip blank J - Estimated value - analyte was present but less than the Reporting Limit (RL) Page 4 of 116

Project: GTNP COLTER BAY LANDFILL

Lab ID: H24090718-001

Client Sample ID: 0919-CBL-101 Collection Date: 09/19/24 07:00

Matrix: Aqueous Report Date: 10/10/24

DateReceived: 09/20/24

Prepared by Helena, MT Branch

Analyses Result Units Analysis Date / ByRL MethodMCLQUAL Prep Date Prep Method RunID

Run

Order BatchID

VOLATILE ORGANIC COMPOUNDS

09/26/24 13:55 / kmh1.0ug/LND1,4-Dichlorobenzene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDtrans-1,4-Dichloro-2-butene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDDichlorodifluoromethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,1-Dichloroethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,2-Dichloroethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,1-Dichloroethene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDcis-1,2-Dichloroethene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDtrans-1,2-Dichloroethene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,2-Dichloropropane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDcis-1,3-Dichloropropene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDtrans-1,3-Dichloropropene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDEthylbenzene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh20ug/LND2-Hexanone SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDIodomethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh20ug/LNDMethyl ethyl ketone SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh20ug/LNDMethyl isobutyl ketone SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDMethylene chloride SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDStyrene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,1,1,2-Tetrachloroethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,1,2,2-Tetrachloroethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDTetrachloroethene SW8260B 5973MSD_240926A : 8 R198901

J 09/26/24 13:55 / kmh1.0ug/L0.41Toluene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,1,1-Trichloroethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,1,2-Trichloroethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDTrichloroethene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDTrichlorofluoromethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LND1,2,3-Trichloropropane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDVinyl acetate SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh1.0ug/LNDVinyl chloride SW8260B 5973MSD_240926A : 8 R198901

J 09/26/24 13:55 / kmh1.0ug/L0.36m+p-Xylenes SW8260B 5973MSD_240926A : 8 R198901

J 09/26/24 13:55 / kmh1.0ug/L0.22o-Xylene SW8260B 5973MSD_240926A : 8 R198901

Report

Definitions:

RL - Analyte Reporting Limit MCL - Maximum Contaminant Level

QCL - Quality Control Limit ND - Not detected at the Reporting Limit (RL)

J - Estimated value - analyte was present but less than the Reporting Limit (RL) Page 5 of 116

Project: GTNP COLTER BAY LANDFILL

Lab ID: H24090718-001

Client Sample ID: 0919-CBL-101 Collection Date: 09/19/24 07:00

Matrix: Aqueous Report Date: 10/10/24

DateReceived: 09/20/24

Prepared by Helena, MT Branch

Analyses Result Units Analysis Date / ByRL MethodMCLQUAL Prep Date Prep Method RunID

Run

Order BatchID

VOLATILE ORGANIC COMPOUNDS

J 09/26/24 13:55 / kmh1.0ug/L0.59Xylenes, Total SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh69-131%REC111 Surr: 1,2-Dichloroethane-d4 SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh70-125%REC111 Surr: Dibromofluoromethane SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh76-123%REC98.0 Surr: p-Bromofluorobenzene SW8260B 5973MSD_240926A : 8 R198901

09/26/24 13:55 / kmh80-119%REC103 Surr: Toluene-d8 SW8260B 5973MSD_240926A : 8 R198901

Report

Definitions:

RL - Analyte Reporting Limit MCL - Maximum Contaminant Level

QCL - Quality Control Limit ND - Not detected at the Reporting Limit (RL)

J - Estimated value - analyte was present but less than the Reporting Limit (RL) Page 6 of 116

Project: GTNP COLTER BAY LANDFILL

Lab ID: H24090718-002

Client Sample ID: 0919-CBL-102 Collection Date: 09/19/24 08:00

Matrix: Aqueous Report Date: 10/10/24

DateReceived: 09/20/24

Prepared by Helena, MT Branch

Analyses Result Units Analysis Date / ByRL MethodMCLQUAL Prep Date Prep Method RunID

Run

Order BatchID

PHYSICAL PROPERTIES

09/20/24 14:29 / SRW200mg/L527Solids, Total Dissolved TDS @ 180 C A2540 C Sartorius-BCA124-1S_240920B : 22 TDS20240920A

INORGANICS

09/23/24 19:59 / eer4mg/L140Alkalinity, Total as CaCO3 A2320 B PHSC_101-H_240923A : 122 R198750

09/23/24 19:59 / eer4mg/L170Bicarbonate as HCO3 A2320 B PHSC_101-H_240923A : 122 R198750

09/23/24 19:59 / eer4mg/LNDCarbonate as CO3 A2320 B PHSC_101-H_240923A : 122 R198750

10/02/24 20:36 / eer1mg/L164Chloride E300.0 IC METROHM_241001A : 123 R199079

10/02/24 20:36 / eer1mg/L14Sulfate E300.0 IC METROHM_241001A : 123 R199079

10/02/24 20:36 / eer0.1mg/LNDFluoride E300.04 IC METROHM_241001A : 123 R199079

09/25/24 17:01 / eli-b0.005mg/LNDCyanide, Total Kelada-01 SUB-B429513 : 56 B_R429513

AGGREGATE ORGANICS

10/08/24 03:31 / eli-b2mg/L13Organic Carbon, Total (TOC) A5310 C SUB-B430222 : 15 B_R430222

09/30/24 18:11 / eer10mg/L64Oxygen Demand, Chemical (COD) E410.4 09/30/24 10:30 HACH 800 GENESYS 20_240930B : 6 74201

NUTRIENTS

10/02/24 15:21 / JAR0.05mg/LNDNitrogen, Ammonia as N E350.1 FIA203-HE_241002A : 164 R199118

10/02/24 08:33 / rrs0.01mg/L0.91Nitrogen, Nitrate as N E353.2 CALC_241002A : 49 241002_INORG

09/30/24 21:34 / JAR0.01mg/L0.99Nitrogen, Nitrate+Nitrite as N E353.2 SEAL AA500_240930B : 188 R199050

09/20/24 12:10 / JAR0.01mg/L0.09Nitrogen, Nitrite as N…