Uranium_2_Final_RA_Report.pdf

FINAL

REMOVAL ACTION REPORT

Uranium 2 Wanigan Spill Cleanup

Uranium 2 Wanigan Spill Site Buckland, Alaska 99727

October 2023

Contract Number: 140L6320P0046

Prepared For

U.S. Department of the Interior Bureau of Land Management Alaska 222 W. 7th Avenue, #13 Anchorage, Alaska 99513-7587

Prepared By

Bethel Environmental Solutions LLC 2605 Denali St., STE 100 Anchorage, AK 99503

FINAL

REMOVAL ACTION REPORT

Uranium 2 Wanigan Spill Cleanup

Uranium 2 Wanigan Spill Site Buckland, Alaska 99727

October 2023

Contract Number: 140L6320P0046

This Report has been prepared by Bethel Environmental Solutions LLC and has been reviewed and approved for distribution.

Quenton Nelson, Project Manager Quenton Nelson Digitally signed by Quenton Nelson

Date: 2023.10.25 13:04:14 -04'00'

Removal Action Report Bureau of Land Management

Uranium 2 Wanigan Spill Cleanup Buckland, Alaska

140L6320P0046 Page i

Table of Contents

Executive Summary ...................................................................................................................... v

1.0 Introduction

1.1 Report Organization

1.2 Physical Setting

1.2.1 Geology/Hydrology

1.3 Site Background

1.4 Project Objectives

1.5 Applicable Cleanup Levels

2.0 Work Performed

2.1 Mobilization and Demobilization

2.2 Site Cleanup

2.3 Soil Excavation

2.4 Field Screening

2.5 Soil Sample Collection

2.5.1 Confirmation Samples

2.5.2 Total Organic Carbon Samples

2.5.3 ISM Samples

2.5.4 General Sample Collection Methods

2.6 Sample Storage, Transport and Chain of Custody Procedures

2.7 Waste Disposal

2.7.1 Landspreading

2.7.2 Decontamination and Investigation-Derived Waste

2.8 Deviations from the Work Plan

3.0 Results

3.1 Observations

3.2 Contaminated Soil Removal

3.3 Excavation Field Screening Results

3.4 Confirmation Soil Sample Results

3.4.1 Fuels Results

3.4.2 VOCs Results

3.4.3 PAH Compounds Results

3.5 Landspread ISM Characterization Soil Sample Results

3.5.1 Fuels Results

3.5.2 VOCs Results

3.5.3 PAH Compounds Results

3.6 Data Quality

4.0 Conclusions and Recommendations

4.1 Conclusions

4.2 Recommendations

Bureau of Land Management Removal Action Report

Buckland, Alaska Uranium 2 Wanigan Spill Cleanup

Page ii 140L6320P0046

5.0 References

List of Figures

Figure 1. Site 9 – Uranium 2 Vicinity Map

Figure 2. Site 9 – Uranium 2 Wanigan Spill Site Map

Figure 3. Uranium 2 Screening and TOC Sample Locations

Figure 4. Sidewall Screening Sample Locations

Figure 5. Uranium 2 Confirmation Sample Locations and Analyte Detections

Figure 6. Uranium 2 Landspread ISM Sample Grid and CUL Exceedances

List of Tables

Table 1-1. Wanigan Spill Site Location Information

Table 1-2. ADEC Soil CULs

Table 3-1. Field Screening Results

List of Appendices

Appendix A: Soil Sample Summary Reporting Tables

Appendix B: Photographic Log

Appendix C: Field Documentation

Appendix D: Analytical Laboratory Report

Appendix E: Data Quality Report

Appendix F: Response to Comments

140L6320P0046 Page iii

Acronyms and Abbreviations

°C degrees Celsius

AAC Alaska Administrative Code

ADEC Alaska Department of Environmental Conservation

AK State of Alaska Method

Bethel Bethel Environmental Solutions LLC bgs below ground surface

BLM Bureau of Land Management

CUL cleanup level

CY cubic yard

DRO diesel-range organics

DU decision unit

EPA Environmental Protection Agency

ft. feet

GPS global positioning system

GRO gasoline-range organics

IDW investigation-derived waste

ISM incremental sampling methodology

ITRC Interstate Technology & Regulatory Council mg/kg milligrams per kilogram

PAH polycyclic aromatic hydrocarbon

PID photoionization detector ppm parts per million

QEP Qualified Environmental Professional

RA Removal Action

RRO residual-range organics

SIM Selected Ion Monitoring

SW Solid Waste Method

TOC total organic carbon

UCL upper confidence limit

VOC volatile organic compound

Page iv 140L6320P0046

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140L6320P0046 Page v

Executive Summary

The U.S. Department of the Interior, Bureau of Land Management Alaska (BLM) contracted

Bethel Environmental Solutions LLC (Bethel) to perform a contaminated soil and non-hazardous solid waste cleanup at an abandoned wanigan (cabin on skids) located 18 miles northwest of

Buckland, Alaska. A wanigan had been abandoned at the site location, which is situated on the crest of a rocky knoll on a mountain spur. The site was a uranium prospect explored decades ago. Amongst the wreckage of the wanigan are wooden planks, corrugated metal roofing, and multiple empty drums. The impacted area of debris is approximately 10 to 15 acres of tundra. A drum leaked an unknown amount of fuel at the wanigan location. Bears had wallowed in the spill creating an approximate 10-foot (ft) by 12-ft by 1-ft depression.

One surface soil sample was collected by BLM from the center of the wallow in 2016.

Laboratory results indicated 2,800 milligrams per kilogram of diesel-range organics (DRO). No other samples were collected and the vertical and lateral extent were unknown. Due to the rocky nature of the site, bedrock was assumed to be shallow.

Bethel performed a removal action in July 2022. The objective of the soil cleanup was to remove up to 10 cubic yards (CY) of contaminated soil exceeding the most stringent ADEC Method Two cleanup levels (CULs). Contaminants of concern included DRO, residual-range organics (RRO), gasoline-range organics (GRO), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). A description of the methods and results of the work performed are presented in the body of this report.

In July 2022, Bethel excavated approximately 10 CY of non-hazardous diesel-contaminated soil.

Due to the remoteness of the site, the excavated contaminated soil was landspread on site, where it will be allowed to naturally attenuate.

Field screening sample were collected and analyzed using the heated headspace method. As prescribed in the work plan, a screening action level of 20 parts per million (ppm), as measured by a photoionization detector, was utilized. Screening samples measuring below 20 ppm were considered clean. Based upon field screening samples, the excavation sidewalls and base were considered clean after the excavation of the contracted 10 CY of soil. Confirmation soil samples were collected from each of the excavation sidewalls, as well as the base. A total of five confirmation samples and one duplicate sample were collected.

After its construction, characterization samples were collected from the landspread using

Incremental Sampling Methodology (ISM) sampling procedures. The landspread was treated as a single decision unit and one ISM sample was collected, as well as a duplicate and triplicate sample.

Additional work conducted at the site included the removal and disposal of one steel 55-gallon drum and the collection of 10 primary and one duplicate total organic carbon (TOC) samples from 10 random locations surrounding the excavation, so that site specific Method Three CULs could be calculated, should the Method Three CULs not be met after the excavation of the contracted 10 CY.

Page vi 140L6320P0046

The confirmation and ISM characterization samples were analyzed for DRO, RRO, GRO, VOCs, and PAHs. All of the analyte concentrations detected in the confirmation samples were determined to be below the respective most stringent ADEC Method Two CUL, when analyzed by the laboratory. DRO was determined to be the only analyte above the applicable ADEC

Method Two CUL in the landspread ISM characterization samples.

Because the ADEC Method Two CULs were met, Method Three CULs were not calculated for this report. The TOC sample results, however, are included.

Based upon the results from the fuel spill cleanup at the Uranium 2 Wanigan Spill site, it is recommended that the former spill location be considered clean, requiring no further action.

The landspread, however, currently consists of soil above the ADEC Migration to Groundwater

CUL for DRO, which is the current most stringent ADEC CUL applicable to the Uranium 2 site.

It is therefore recommended that the landspread be monitored periodically using ISM sampling techniques to characterize the soil. Because the natural attenuation of the landspread is likely to progress somewhat slowly, an attenuation period of three to five years is recommended between sampling events. The next sampling event should occur sometime between 2025 and

2027.

This Executive Summary is provided for the convenience of the reader and should not be relied upon without considering the entire report.

140L6320P0046 Page 1

1.0 INTRODUCTION

The U.S. Department of the Interior, Bureau of Land Management (BLM) contracted Bethel

Environmental Solutions LLC (Bethel) to perform a contaminated soil and non-hazardous solid waste cleanup at an abandoned wanigan (cabin on skids) located 18 miles northeast of

Buckland, Alaska. A wanigan was abandoned at the site location, which is situated on the crest of a rocky knoll on a mountain spur.

Work was completed in accordance with the BLM Statement of Work, Bethel’s proposal dated

23 September 2020, Final Work Plan, Uranium 2 Wanigan Spill Cleanup, Buckland Alaska

(Bethel, 2022), and the Alaska Department of Environmental Conservation (ADEC) Field

Sampling Guidance (ADEC, 2022).

1.1 Report Organization

This report is organized into the following sections:

● Section 1, Introduction. This section describes the physical setting of the site, including the geology, groundwater source and usage, and climate.

● Section 2, Work Performed. This section describes the field activities that took place in

2022.

● Section 3, Results. This section provides results for the 2022 Removal Action (RA). This section also includes a discussion of the results of the laboratory data review.

● Section 4, Conclusions and Recommendations. This section provides conclusions and recommendations for the 2023 RA.

● Section 5, References. This section lists references that were used in development of this report.

● Appendix A. Soil Sample Summary Reporting Tables

● Appendix B. Photographic Log

● Appendix C. Field Documentation

● Appendix D. Analytical Laboratory Report

● Appendix E. Data Quality Report

● Appendix F. Response to Comments

1.2 Physical Setting

The site is located approximately 18 miles northeast of Buckland and is accessible by air from the Buckland airstrip. Location information is provided in Table 1-1.

Page 2 140L6320P0046

Table 1-1. Wanigan Spill Site Location Information

Township and Range Northing

(U.S. survey feet)

Easting

(U.S. survey feet)

NW1/4 Section 6, Township 08 North, Range 09 West, Kateel River Meridian

4433563.466394 1843273.027188

The site falls within the arctic climate zone, characterized by seasonal extremes in temperature.

Winters are long and harsh and summers are short but warm. Crosswinds can restrict flying to and from Buckland during the winter (State of Alaska Department of Community and Regional

Affairs, 2021). The average annual precipitation is between 18 and 20 inches per year (US

Forest Service, 2022). See Figure 1 for the site location and vicinity.

1.2.1 Geology/Hydrology

The site is situated on the crest of a rocky knoll on a mountain spur composed of weathered granite. The crest of the spur is dry and sparsely covered with tundra. Two creeks flow parallel to the spur, down the re-entrants on either side, joining a larger creek flowing through the valley at the toe of the spur. Moisture increased down the sides of the spur with areas of marshy tundra and tundra ponds increasing as one approaches the creeks. Possible indications of limited groundwater was encountered at approximately 6 feet below the ground surface, just above bedrock, in the excavation at the crest of the knoll, however, heavy rainfall persisted throughout the project. It is unlikely that groundwater would be encountered at this depth in this location during drier months.

1.3 Site Background

A wanigan was abandoned at the site location. The site was a uranium prospect explored decades ago. Amongst the wreckage of the wanigan are wood planks and corrugated metal roofing from the wanigan and multiple empty drums. The impacted area of debris is approximately 10 to 15 acres on tundra. A drum leaked an unknown amount of fuel at the wanigan location. Bears had wallowed in the spill, creating an approximate 10-foot (ft) by 12-ft by 1-ft depression.

One surface soil sample was collected by BLM from the center of the wallow in 2016.

Laboratory results indicated 2,800 milligrams per kilogram (mg/kg) diesel-range organics

(DRO). No other samples were collected and the vertical and lateral extent were unknown. Due to the rocky nature of the site, bedrock was assumed to be shallow.

1.4 Project Objectives

The objectives of the work were to conduct an RA at the site of the known fuel spill at the wanigan spill site, including the following:

● mobilize field personnel from Anchorage to the wanigan spill site;

● remove contaminated soil with a limit of 10 cubic yards (CY);

● collect the required number of field screening samples from the excavation limits and test them with a photoionization detector (PID);

140L6320P0046 Page 3

● collect the required number of confirmation soil samples from the final excavation limits;

● landspread the contaminated soil removed from the excavation;

● collect one baseline triplicate Incremental Sampling Methodology (ISM) sample from the landspread area;

● remove and dispose of up to 10 empty rusted 55-gallon drums; and

● regrade the excavation sidewalls to resemble natural conditions and prevent human and/or animal entrapment.

1.5 Applicable Cleanup Levels

The ADEC Contaminated Sites Program does not list the site on their contaminated sites database. Applicable soil ADEC cleanup levels (CULs) are the most stringent listed in 18 Alaska

Administrative Code (AAC) 75 Oil and other Hazardous Substances Pollution Control, Tables

B1 and B2 Under 40-inch Zone (ADEC, 2021). For most compounds, the Migration to

Groundwater CULs are the most stringent, but Human Health (direct contact) CULs are more stringent for some volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons

(PAHs). A summary of the CULs is listed in Table 1-2.

Table 1-2. ADEC Soil CULs

Contaminant Soil

(mg/kg)

Fuels by AK101, AK102 & AK103

GRO 300

DRO 250

RRO 11,000

Fuel-Related VOCs by SW8260C

Benzene 0.022

Ethylbenzene 0.13

Toluene 6.7

Xylenes (total) 1.5

Other VOCs Varies by Compound

PAHs by SW8270D-SIM

1-Methylnaphthalene 0.41

2-Methylnaphthalene 1.3

Acenaphthene 37

Acenaphthylene 18

Anthracene 390

Benz(a)anthracene 0.28

Benzo[a]pyrene 0.27

Page 4 140L6320P0046

Contaminant Soil

(mg/kg)

Benzo[b]fluoranthene 2.0

Benzo[g,h,i]perylene 2,300

Benzo[k]fluoranthene 20

Chrysene 82

Dibenzo[a,h]anthracene 0.20*

Fluoranthene 590

Fluorene 36

Indeno[1,2,3-c,d] pyrene 2.0*

Naphthalene 0.038

Phenanthrene 39

Pyrene 87

AK = Alaska Method GRO = gasoline-range organics RRO = residual-range organics SIM = selected ion monitoring SW = solid waste method See Acronyms and Abbreviations for other definitions.

Selawik Lake

Eschscholtz Bay

Selawik

Buckland

Site 9

Drawn By: Contract No:Date:

SS March 2023

Figure 1

Site 9 - Uranium 2 Vicinity Map

BLM Abandoned Cabin Sites Buckland, Alaska

Notes:

1. Image Source: Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community Copyright:© 2013 National Geographic Society, i-cubed

Site 9 Buckland

Nome

McGrath

Kotzebue

Fairbanks Unalakleet

Glennallen

Bethel Environmental Solutions LLC 2605 Denali Street

Anchorage, Alaska 99503

Alaska State Plane Zone 7 U. S. Survey Feet

Horizontal Datum: NAD 1983 (2011)

¹ 0 21,000 42,00010,500 Feet

140L6320P0046

Page 6 140L6320P0046

Approximate Original Battery Location

Approximate Curremt Battery Location

Approximate Former Drum Location

Drawn By: Contract No:Date:

SS March 2023

Figure 2

Site 9 - Uranium 2 Wanigan Spill Site Map

BLM Abandoned Cabin Sites Buckland, Alaska

Notes:

1. Image Source: Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community

USAF (2016)

Wanigan Spill Location

Buckland

Bethel Environmental Solutions LLC 2605 Denali Street

Anchorage, Alaska 99503

Alaska State Plane Zone 7 U. S. Survey Feet

Horizontal Datum: NAD 1983 (2011)

Legend #* Total Organic Carbon Sample Locations

Excavation Boundary

Landspread Area

¹ 0 75 15037.5

Page 8 140L6320P0046

140L6320P0046 Page 9

2.0 WORK PERFORMED

Field activities were completed in accordance with the Final Work Plan Uranium 2 Wanigan Spill

Cleanup (Bethel, 2022) and the ADEC Field Sampling Guidance (ADEC, 2022), and included the excavation and landspread of between 10.2 to 10.7 CY of contaminated soil; the collection, removal, and disposal of one 55-gallon drum; the collection of confirmation samples from the sidewalls and floor of the excavation; the collection of eleven randomly spaced total organic carbon (TOC) samples, including a duplicate; and the ISM sampling of the landspread. The following sections describe the activities conducted and methods used for each task performed during the RA. Appendix B contains photographs of key field activities. Appendix C contains field notes.

2.1 Mobilization and Demobilization

The work was performed in July 2022. Bethel personnel mobilized to the site over the course of three days, 21 through 23 July 2022 via various commercial airlines and camped on site during the mobilization. A BLM-provided Kubota mini-backhoe was utilized for the excavation and was mobilized from Anchorage to Buckland via commercial airfreight providers and was slung to the site via helicopter. Bethel environmental scientist Quenton Nelson, an ADEC Qualified

Environmental Professional (QEP), supervised the removal of soil and conducted field screening and laboratory sample collection. He was assisted by Bethel employees Liz Hodges, who is a QEP and assisted in sample collection and other tasks, and Glenn Zisa, who operated the mini-backhoe. Bethel personnel completed site work on 29 July and departed the site for

Buckland on 30 July.

2.2 Site Cleanup

Work required by the contract included the removal and disposal of up to ten empty/rusted 55-gallon drums, although the number of drums actually on site was not known. Despite multiple searches on site and in areas around the site in all cardinal directions, only one 55-gallon drum was found. Staining or other indications of a release from this drum were not observed at location where it was discovered. The drum was empty and completely dry on its inside. The location where the drum was discovered was not survey, but the approximate location is included on Figure 2. This drum was transported to Nome and disposed of at the Nome dump.

A receipt for disposal was not provided and therefore could not be included with this report.

While searching for the drums, a cracked vehicle battery was discovered on the western slope of the spur on which the excavation was located. The battery appears to be a bottle supplied battery that is shipped dry and activated later by the addition of electrolytes. As seen in the photo, multiple seals are missing from the ports where the electrolytes would have been added.

Both the missing ports and the existence of a crack in the battery are likely indications that the battery has leaked. The battery was initially picked up to be transported back to basecamp for subsequent disposal. However, while enroute to the basecamp, it was determined that the proper containment necessary to transport the battery was not on hand and the disposal of hazardous materials was not within the scope of the contract. The battery was left on site. The approximate original and current locations of the battery are included on Figure 2.

Page 10 140L6320P0046

Although a significant quantity of other wooden and metal material originating from the wanigan were present on site, these materials were left in place as they are considered to potentially be of historic value. These materials were not disturbed.

2.3 Soil Excavation

Excavation of contaminated soil began on 24 July and ended on 27 July. A mini-backhoe operated by qualified personnel was used to excavate soil. Once excavated, contaminated soil was deposited directly from the back-hoe bucket into a six-cubic-foot wheelbarrow, as a means of measuring the volume of soil excavated. Cobbles six inches or greater in diameter were removed from the wheelbarrow and piled near to the hole to be used as back fill, as permitted by the ADEC Technical Memorandum Petroleum Hydrocarbon Cleanup for Oversize Materials

(ADEC, 2005). Hydrocarbons do not normally adhere significantly to sediment of this size;

separating it from smaller sediment ensures that the yardage calculated to have been removed reflects the actual contaminated sediments. Once full, the wheelbarrow was pushed to the prepared land spread area and dumped. Subsequent loads were dumped from the wheelbarrow in regularly spaced piles to ensure the soil could be easily hand spread to the required landspread thickness of 4 to 6 inches.

The excavation began at the center of the bear wallow, where the contaminated sample had previously been collected, and extended laterally and vertically as determined by the QEP, using PID readings and olfactory observations to screen the soil as it was excavated. Per the contract, an attempt was not made to separate any overburden. See Appendix B for photographs of the excavation and excavation process.

A total of 46 wheelbarrow loads were excavated. At 6 cubic feet per wheelbarrow load, that is

276 cubic feet or 10.2 CY. The total dimensions of the final excavation were 8 ft long, by 6 ft wide, by 6 ft deep. If the excavation dimensions are used to calculated the volume of soil excavated, 10.7 CY of soil were excavated. The difference in total CY excavated between the two methods of calculating is likely accounted for by the 6-inch plus cobbles that were removed from the excavated soil and the compaction of the soil before excavation.

2.4 Field Screening

The PID was calibrated using 100 parts per million (ppm) isobutylene and a clean air blank prior to use each day. Heated headspace field screening was conducted in accordance the approved work plan and 2022 ADEC Field Sampling Guidance (Bethel, 2022; ADEC, 2022). Once preliminary field screenings indicated that contaminated soil above 20 ppm had been removed from all four side walls as well as the floor, the final field screening samples were collected from the four sidewalls and floor, following Table 2B of the ADEC Field Sample Guidance (ADEC, 2022). Six field screening samples were collected from each excavation sidewall and five were collected from the floor of the excavation. The field screening locations were measured using a survey -grade global positioning system (GPS) to plus or minus one foot horizontal and 0.1-foot vertical accuracy. See Figure 3 for locations of the excavation boundary and field screening sample locations. Since changes in lithology were not observed in the excavation, it was determined that the samples would be equally spaced on the side walls. See Figure 4 for sketches of the vertical and horizontal spacing of the field screening samples in the sidewalls of

140L6320P0046 Page 11 the excavation. Section 3.3 presents a discussion of the field screening results from the excavation.

2.5 Soil Sample Collection

2.5.1 Confirmation Samples

Confirmation soil samples were collected using disposable sample spoons from each of the excavation sidewalls and floor in accordance with Table 2B of the 2022 ADEC Field Sampling

Guidance (ADEC, 2022). A total of five confirmation samples and one duplicate sample were collected:

● the northern sidewall confirmation sample was identified as UW-NSW-SS02 and was collected at a depth of 4.7 feet below ground surface (bgs);

● the southern sidewall confirmation sample was identified as UW-SSW-SS03 and was collected at a depth of 4.7 feet bgs;

● the eastern sidewall confirmation sample was identified as UW-ESW-SS04 and was collected at a depth of 1.75 feet bgs. A duplicate of this sample was collected and was identified as UW-ESW-SS06;

● the western sidewall confirmation sample was identified as UW-WSW-SS05 and was collected at a depth of 1.75 feet bgs; and

● the floor of the excavation confirmation sample was identified as UW-B-SS01 and collected at a depth of 6 feet bgs.

The confirmation locations were measured using a survey-grade GPS to plus or minus one foot horizontal and 0.1-foot vertical accuracy. See Figure 5 for the confirmation sample locations.

2.5.2 Total Organic Carbon Samples

Using the mini-backhoe, ten test pits were advanced in random locations surrounding the excavation to varying depths corresponding to those in the excavation. Ten TOC samples, one from the bottom of each test pit and one duplicate sample were collected, for the purpose of calculating a Method Three Alternative CULs, if necessary. See Figure 3 for the TOC sample locations.

2.5.3 ISM Samples

A single ISM sample, including a duplicate and triplicate sample was collected from the landspread for baseline characterization purposes. ISM procedures described by the Interstate

Technology & Regulatory Council (ITRC) were followed (ITRC, 2020).

For the purposes of ISM sampling, the landspread was considered to be a single decision unit

(DU). A thirty-point grid, composed of thirty rectangular segments defined by six columns and five rows, was established atop the landspread. Each rectangular segment was then divided into four quadrants and one quadrant was randomly selected to be the sampling point from which a subsample would be collected from each of the gird segments, resulting in thirty sub-samples. Each of the thirty sub-samples was collected from an approximate depth of two inches

Page 12 140L6320P0046 and composited with the remaining 29 subsamples, resulting a single ISM sample. The duplicate and triplicate were collected following the same procedures. The duplicate subsamples were collected from one of the three remaining unsampled rectangle quadrants, while the triplicate subsamples were collected from one of the two remaining unsampled rectangle quadrants, ensuring that no segment quadrant was sampled more than once. The four corners of the landspread were measured using a survey-grade GPS to plus or minus one foot horizontal and 0.1-foot vertical accuracy. Figure 6 depicts the ISM sampling grid layout.

2.5.4 General Sample Collection Methods

Analytical soil samples collection followed the protocols outlined in the Final Work Plan Uranium

2 Wanigan Spill Cleanup (Bethel, 2022). Samples were collected in the appropriate certified-cleaned laboratory-provided glass sample jars with Teflon-lined lids. Sample containers were filled as required by the analytical method. For field-preserved methods, such as GRO and

VOCs, 25 milliliters of laboratory-provided methanol with surrogate were added to a pre-tared

4-ounce jar immediately prior to sample collection. Next, approximately 50 grams of soil were quickly placed in the jar, ensuring the soil was completely covered in methanol. Samples analyzed for volatile components were collected first, followed by semi-volatiles, then non-volatile analytes. For unpreserved sample aliquots, containers were filled to the top with care taken to prevent soil from touching the lid threads, which could compromise the integrity of the seal.

Soil samples were submitted to SGS Laboratory in Anchorage, Alaska. Analytical methods employed for this project included the following:

● GRO by AK 101;

● DRO by AK 102;

● RRO by AK 103;

● VOCs by US Environmental Protection Agency (EPA) Solid Waste Method (SW)8260D;

● PAHs by EPA Method 8270D-SIM; and

● TOC by EPA Method SW9060A-Mod.

Figure 5 shows the locations of all of the confirmation soil samples collected within the excavation boundary. One duplicate sample was collected (UW-ESW-SS06). Results are discussed in Section 3.0.

2.6 Sample Storage, Transport and Chain of Custody Procedures

Due to the remoteness of the location and duration of the project, frozen gel ice could not be kept frozen throughout the duration of the field effort. Frozen gel ice was, therefore, not available immediately following collection. To compensate, the collection of samples was delayed as long as possible and samples were not collected until the last full day on site, the day before the morning extraction from the site by helicopter. Ambient daytime air temperatures were in the 40s and low 50s degrees Fahrenheit. Once collected, samples were placed in a cooler and the cooler was placed in the area shaded by vegetation. Frozen gel ice was added to the cooler the next morning, immediately upon arrival in Buckland, and maintained at 4 degrees

140L6320P0046 Page 13

Celsius (°C) ± 2 °C. Samples remained in coolers and chilled with gel ice until flown via Bering

Air to Nome, Alaska on 30 July 2022 and to Anchorage, Alaska on 31 July 2022 via Alaska Air

Cargo, where they were delivered by Bethel personnel to the SGS Laboratory. The analytical report is provided in Appendix D.

2.7 Waste Disposal

2.7.1 Landspreading

The excavated soil was spread on site in a 31-ft square that had previously been stripped of vegetation, to an approximate thickness of four inches, creating a landspread where the soil will be allowed to naturally attenuate. The soil was spread using a combination of the backhoe loader bucket and hand rakes. Once spread to a final thickness of approximately four inches, the landspread was raked in an east-west direction to create furrows parallel to prevailing winds to aide in the natural attenuation of the soil. The four corners of the landspread were measured using a survey-grade GPS to ±1-foot horizontal and 0.1-foot vertical accuracy. For the purpose of identifying the landspread for future follow-up sampling events, the landspread can be identified by connecting the landspread’s four surveyed corners with lines. The area of land encompassed by these lines constitutes the landspread.

2.7.2 Decontamination and Investigation-Derived Waste

Investigation-derived waste (IDW) consisted of disposable sampling equipment and personal protective equipment. IDW was disposed of as solid waste at the Nome Landfill. Any soil remaining on the non-disposable hand tools, such as shovels and rakes was scraped off and the hand tools were scrubbed utilizing an Alconox wash, followed by a freshwater rinse. The same procedure was followed on the mini-backhoe loader bucket, excavator bucket, and tires.

2.8 Deviations from the Work Plan

No deviations from the work plans have been identified.

Page 14 140L6320P0046

E-SW-1

E-SW-3

E-SW-5

B-01

B-04

B-05

B-03

B-02

N-SW-1

N-SW-4

N-SW-2

N-SW-5

N-SW-3

N-SW-6

S-SW-1

S-SW-4

S-SW-2

S-SW-5

S-SW-3

S-SW-6

E-SW-2

E-SW-4

E-SW-6

W-SW-1

W-SW-3

W-SW-5

W-SW-2

W-SW-4

W-SW-6

TOC.1

TOC.2

TOC.3

TOC.4

TOC.5

TOC.6

TOC.7

TOC.8

TOC.9

TOC.10

Drawn By: Contract No:Date:

SS April 2023

Figure 3

Uranium 2 Screening and TOC Sample Locations

BLM Abandoned Cabin Sites Buckland, Alaska

Notes:

1. Image Source: Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community

USAF (2016)

Wanigan Spill Location

Buckland

Kotzebue

Bethel Environmental Solutions LLC 2605 Denali Street

Anchorage, Alaska 99503

Alaska State Plane Zone 7 U. S. Survey Feet

Horizontal Datum: NAD 1983 (2011)

Legend Excavation Sample Locations

#* Total Organic Carbon Sample Locations

Excavation Boundary

¹ 0 5 102.5

Page 16 140L6320P0046

Drawn By: Contract No:Date:

SS April 2023

Figure 4

Sidewall Screening Sample Locations

BLM Abandoned Cabin Sites Buckland, Alaska

Wanigan Spill Location

Buckland

Kotzebue

Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community

Bethel Environmental Solutions LLC 2605 Denali Street

Anchorage, Alaska 99503

Page 18 140L6320P0046

GRO (mg/kg) 0.968 J DRO (mg/kg) 15.6 J

UW-ESW-SS04

GRO (mg/kg) 0.920 J DRO (mg/kg) 39.2

UW-ESW-SS06

GRO (mg/kg) 0.788 J

UW-NSW-SS02

GRO (mg/kg) 0.854 J DRO (mg/kg) 16.7 J

UW-SSW-SS03

GRO (mg/kg) 1.12 J

UW-WSW-SS05

GRO (mg/kg) 0.762 J DRO (mg/kg) 41.3 Toluene ( µg/kg) 27.4

UW-B-SS01

B-03

N-SW-1

S-SW-2

E-SW-6

W-SW-1

Drawn By: Contract No:Date:

SS April 2023

Figure 5

Uranium 2 Confirmation Sample Locations and Analyte Detections

BLM Abandoned Cabin Sites Buckland, Alaska

Notes:

1. Image Source: World Imagery (Clarity): Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community

USAF (2016)

Wanigan Spill Location

Buckland

Kotzebue

Bethel Environmental Solutions LLC 2605 Denali Street

Anchorage, Alaska 99503

Alaska State Plane Zone 7 U. S. Survey Feet

Horizontal Datum: NAD 1983 (2011)

Legend Confirmation_Sample_Locs

Excavation Boundary

0 3.5 71.75 Feet

140L6320P0046 GRO (mg/kg) 300 DRO (mg/kg) 250 Toluene ( µg/kg) 6,700

Applicable CUL

Page 20 140L6320P0046

Drawn By: Contract No:Date:

SS April 2023

Figure 6

Uranium 2 Landspread ISM Sample Grid and CUL Exceedances

BLM Abandoned Cabin Sites Buckland, Alaska

Notes:

1. Image Source: Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community

USAF (2016)

Wanigan Spill Location

Buckland

Bethel Environmental Solutions LLC 2605 Denali Street

Anchorage, Alaska 99503

Alaska State Plane Zone 7 U. S. Survey Feet

Horizontal Datum: NAD 1983 (2011)

¹ 0 4 82 Feet

140L6320P0046

Primary Sample DRO (mg/kg) 489 Duplicate Sample DRO (mg/kg) 504 Triplicate Sample DRO (mg/kg) 485 DRO 95% UCL (mg/kg) 509.6

Landspread ISM Results above the CUL

Legend DU Segment Boundaries

DU Segment Quadrant Boundaries

DRO (mg/kg) 250 Applicable CUL

Page 22 140L6320P0046

140L6320P0046 Page 23

3.0 RESULTS

Results of the 2022 RA are provided in this section. Soil sample analytical results are compared with ADEC Method Two CULs promulgated in 18 AAC 75 Articles 3 and 9, Oil and Other

Hazardous Substance Pollution Control Regulations (ADEC, 2021). Data tables of the analytical results are provided in Appendix A.

3.1 Observations

During excavation, only one lithographic unit was encountered, a damp, reddish brown silty sand with cobbles. Possible indications of limited groundwater were encountered in isolated locations at the bottom of the excavation, approximately 6 feet bgs. However, this water may have been a result of the persistent rain throughout duration of the project. It is unlikely that water is present at this depth during drier periods.

3.2 Contaminated Soil Removal

A total of between 10.2 to 10.7 CY of contaminated soil were removed during the excavation.

Estimations of the total volume differ based upon the method of estimating. Based upon field screening and olfactory observations, the four walls and floor of the excavation were all considered clean.

3.3 Excavation Field Screening Results

Results from 29 field screening samples collected at the excavation are provided on Table 3-1.

The excavation field screening sample locations are shown in Figure 3 and Figure 4 for the excavation sidewalls and Figure 3 for the excavation floor locations. PID field screening results ranged from 0 ppm to 5.8 ppm.

Table 3-1. Field Screening Results

PID Screening Sample

Location in

Excavation

Depth Collected

(ft bgs)

Result

(ppm)

Corresponding

Confirmation Sample

E-SW-01 Sidewall-East 5.25 1.43 NA

E-SW-02 Sidewall-East 5.25 1.498 NA

E-SW-03 Sidewall-East 3.5 1.685 NA

E-SW-04 Sidewall-East 3.5 3.115 NA

E-SW-05 Sidewall-East 1.75 3.043 NA

E-SW-06 Sidewall-East 1.75 6.201

UW-ESW-SS04 &

UW-ESW-SS06

N-SW-01 Sidewall-North 4.7 2.714 UW-NSW-SS02

N-SW-02 Sidewall-North 4.7 2.463 NA

N-SW-03 Sidewall-North 4.7 1.552 NA

N-SW-04 Sidewall-North 2.4 1.768 NA

N-SW-05 Sidewall-North 2.4 1.87 NA

Page 24 140L6320P0046

PID Screening Sample

Location in

Excavation

Depth Collected

(ft bgs)

Result

(ppm)

Corresponding

Confirmation Sample

N-SW-06 Sidewall-North 2.4 0.993 NA

S-SW-01 Sidewall-South 4.7 1.094 NA

S-SW-02 Sidewall-South 4.7 3.102 UW-SSW-SS03

S-SW-03 Sidewall-South 4.7 2.522 NA

S-SW-04 Sidewall-South 2.4 1.657 NA

S-SW-05 Sidewall-South 2.4 1.652 NA

S-SW-06 Sidewall-South 2.4 1.928 NA

W-SW-01 Sidewall-West 5.25 7.604 UW-WSW-SS05

W-SW-02 Sidewall-West 5.25 0.531 NA

W-SW-03 Sidewall-West 3.5 1.06 NA

W-SW-04 Sidewall-West 3.5 1.345 NA

W-SW-05 Sidewall-West 1.75 1.34 NA

W-SW-06 Sidewall-West 1.75 1.139 NA

B-01 Base 6 1.084 NA

B-02 Base 6 2.061 NA

B-03 Base 6 5.94 UW-B-S001

B-04 Base 6 1.245 NA

B-05 Base 6 0.964 NA

See Acronyms and Abbreviations for definitions.

3.4 Confirmation Soil Sample Results

Soil confirmation samples were analyzed for GRO, DRO, RRO, VOCs, and PAHs. Table A-1 in

Appendix A presents the complete soil sample results, where they are compared to the most stringent of the ADEC CULs listed in Tables B1 and B2 Under 40-inch Zone of the 18 Alaska

Administrative Code 75 (18 AAC 75) Oil and Other hazardous Substances Pollution Control

(ADEC, 2021). In most cases, the Migration to Groundwater CULs are the most stringent, but

Human Health (direct contact) CULs are more stringent for some VOCs and PAHs. Figure 5 shows the sample locations and the detectable analyte results.

3.4.1 Fuels Results

Confirmation sample results for GRO, DRO, and RRO were below the applicable ADEC CULs of 300, 250, and 11,000 mg/kg, respectively, in each of the samples. GRO was detected in all six confirmation samples, including the duplicate, with sample UW-WSW-SS05, from the west sidewall having the highest concentration, 1.12 J mg/kg. DRO was detected in four of the six samples, including the duplicate, with sample UW-ESE-SS06, from the east wall, having the highest concentration, 39.2 mg/kg. RRO was not detected in any of the confirmation samples.

140L6320P0046 Page 25

3.4.2 VOCs Results

No VOCs were detected above their respective applicable CUL. Two VOCs, however, 1,2,3-Trichloropropane and 1,2-Dibromoethane, although not detected in any of the confirmation samples, had analysis detection limits greater than the applicable CULs of 0.031 and 0.24 mg/kg, respectively. Although it cannot be definitively stated that these analytes were not present in the samples at concentrations above the applicable respective CULs, their presence at concentrations above the CULs is highly unlikely, given the concentrations of the other VOC analytes in the samples.

3.4.3 PAH Compounds Results

No PAH compounds were detected above their applicable respective CULs.

3.5 Landspread ISM Characterization Soil Sample Results

A single DU ISM soil sample, including a duplicate and a triplicate was collected to characterize the landspread and was analyzed for GRO, DRO, RRO, VOCs, and PAHs. Table A-2 in

Appendix A presents the complete soil sample results, where they are compared to the most stringent of the ADEC CULs listed in Tables B1 and B2 Under 40-inch Zone of the 18 AAC 75

Oil and Other hazardous Substances Pollution Control (ADEC, 2021). In most cases, the

Migration to Groundwater CULs are the most stringent, but Human Health (direct contact) CULs are more stringent for some VOCs and PAHs. Figure 6 shows the ISM sampling grid layout with the results exceeding the respective applicable results.

3.5.1 Fuels Results

DRO was detected above the respective applicable ADEC CUL of 250 mg/kg in the primary, duplicate, and triplicate landspread ISM samples, at concentrations of 489, 504, and 485 mg/kg, respectively. Using the DRO concentrations from the primary, duplicate, and triplicate samples, a 95% upper confidence limit (UCL) of the arithmetic mean was calculated for DRO using the procedures and calculations detailed in the ITRC’s Incremental Sampling Methodology Update

(ITRC, 2020). These calculations resulted in a 95% UCL of 509.6 mg/kg, indicating that, with

95% confidence, the true average concentration of the soil in the landfill is below 509.6 mg/kg.

GRO and RRO were not detected above the respective applicable ADEC CULs of 300 and

11,000 mg/kg, respectively, in the primary, duplicate, and triplicate ISM samples. The highest

GRO detection was 2.13 J mg/kg, while the highest RRO detection was 176 mg/kg. These concentrations are far below the relevant CUL and do not warrant the calculation of a 95% UCL for these compounds.

3.5.2 VOCs Results

No VOCs were detected in the ISM samples. As with the confirmation samples, however, 1,2,3-Trichloropropane and 1,2-Dibromoethane were not detected in any of the ISM samples, however, the analyses for these compounds had detection limits greater than the applicable

CULs of 0.031 and 0.24 mg/kg, respectively. Although it cannot be definitively stated that these analytes were not present in the samples at concentrations above the applicable respective

CULs, their presence at concentrations above the CULs is highly unlikely give the

Page 26 140L6320P0046 concentrations of the other VOC analytes in the samples. Given that VOCs were not detected in the samples, the calculation of a 95% UCL for these compounds was not necessary and could not be performed.

3.5.3 PAH Compounds Results

Pyrene is the only PAH compound that was detected in the ISM samples. Given that the highest

Pyrene concentration was 24.5 J micrograms per kilogram (µg/kg), while the applicable CUL is

87,000 µg/kg, the calculation of a 95% UCL for Pyrene was not necessary, as Pyrene concentrations in the landspread are far below the respective applicable CUL.

3.6 Data Quality

A data quality assessment of laboratory data for soil samples was performed on the laboratory data, according to the guidelines described in the ADEC Technical Memorandum, Data Quality

Objectives, Checklists, Quality Assurance Requirements for Laboratory Data and Sample

Handling (ADEC, 2017). Laboratory data were evaluated using laboratory-supplied control criteria. The data review included assessments of holding times, blanks, matrix spike/matrix spike duplicate and laboratory control spike sample recoveries, duplicate sample relative percent differences, reporting limits, and an overall assessment of the data.

Appendix E contains the data quality assessment, which includes an ADEC Laboratory

Checklist for the data package. Appendix D contains the Level II Laboratory Data Report.

The data validation review determined the overall quality of the Uranium 2 cleanup samples to be acceptable. Precision, accuracy, representativeness, comparability, and completeness were deemed acceptable and the data are usable for the purposes of this project. Project sample results affected by quality control anomalies have been flagged accordingly.

140L6320P0046 Page 27

4.0 CONCLUSIONS AND RECOMMENDATIONS

An RA was conducted for a fuel spill at the Uranium 2 site, near Buckland, AK. The RA was performed with the objective of removing contaminated soil above the most stringent ADEC

Method Two CULs. Although background TOC samples were collected from the site so that site-specific Method Three CULs could be calculated if the ADEC Method Two CULs were not met after the excavation of the contracted 10 CY, this report has not presented Method Three

CULs, as the Method Two CULs were met. The TOC sample results, however, are presented in

Table A-3 in Appendix A. Conclusions from this RA are discussed below.

4.1 Conclusions

The excavation removed between 10.2 and 10.7 CY of contaminated soil. Six characterization soil samples were collected from the excavation, including one duplicate sample. These samples were analyzed for DRO, RRO, GRO, VOCs, and PAHs. Analyte concentrations were below the most stringent ADEC Method Two CULs in all confirmation samples, indicating that all soil exceeding the Method Two CULs related to the Uranium 2 wanigan spill has been excavated.

The excavated soil was subsequently spread in a 31-foot square landspread to a thickness of four inches, to optimize conditions for natural attenuation. A grid was then established atop the landspread and the landspread was sampled using ISM sampling methods to characterize the soil. The ISM primary, duplicate, and triplicate samples were analyzed by a laboratory for DRO, RRO, GRO, VOCs, and PAHs. The analytical results of these samples indicated that the soil in the landspread was above the most stringent ADEC Method Two CUL for DRO. DRO concentrations from the primary, duplicate, and triplicate samples were used to calculate a 95%

UCL of 509.6 mg/kg, indicating with 95% confidence that the average concentration of DRO in the landspread soil was below 509.6 mg/kg at the time of the construction of the landspread.

4.2 Recommendations

Based upon the conclusions from the fuel spill cleanup at the Uranium 2 Wanigan Spill site, it is recommended that the former spill location be considered clean, requiring no further action.

The landspread, however, currently consists of soil above the ADEC Migration to Groundwater

CUL for DRO, which is the current most stringent ADEC CUL applicable to the Uranium 2 site. It is therefore recommended that the landspread be monitored periodically using ISM sampling techniques to characterize the soil. Because the natural attenuation of the landspread is likely to progress somewhat slowly, an attenuation period of three to five years is recommended between sampling events. The next sampling event should occur sometime between 2025 and

2027.

Page 28 140L6320P0046

140L6320P0046 Page 29

5.0 REFERENCES

ADEC. (2005, September 1). Technical Memorandum. Petroleum Hydrocarbon Cleanup for

Oversized Material.

ADEC. (2017, March). Technical Memorandum. Data Quality Objectives, Checklists, Quality

Assurance Requirements for Laboratory Data and Sample Handling.

ADEC. (2021, November). Oil and Other Hazardous Substance Pollution Control: Title 18, Alaska Administrative Code, Chapter 75.

ADEC. (2022, January). Field Sampling Guidance.

Bethel. (2022, July). Final Work Plan, Uranium 2 Wanigan Spill Cleanup, Buckland, Alaska.

ITRC. (2020, February). Incremental Sampling Methodology.

State of Alaska Department of Community and Regional Affairs. (2021, August 18). Digital Data for Communities. Retrieved from https://dcra-cdo-dcced.opendata.arcgis.com

US Forest Service. (2022, August 29). Historical Annual Precipitation (Alaska). Retrieved April

18, 2023, from https://hub.arcgis.com/datasets/80907fbc5b6c4512951da227ddf4758b/explore

Page 30 140L6320P0046

140L6320P0046 Appendix A

Appendix A:

Soil Sample Summary Reporting Tables

Appendix A 140L6320P0046

Job1224523 Client Sample ID: UW-B-SS01 UW-NSW-SS02 UW-SSW-SS03 UW-ESW-SS04 UW-WSW-SS05

UW-ESW-SS06

(Duplicate of UW-ESW-SS04)

UW-TB01

Description:

BLM Uranium 2

Lab Sample ID: 1224523001 1224523002 1224523003 1224523004 1224523005 1224523006 1224523010

Matrix: Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry weight)

Location: Base of Excavation North Sidewall South Sidewall East Sidewall West Sidewall East Sidewall FieldQC

Sample Date: 7/29/2022 10:15 AM 7/29/2022 10:23 AM 7/29/2022 10:26 AM 7/29/2022 10:30 AM 7/29/2022 10:42 AM 7/29/2022 10:35 AM 7/29/2022 10:15 AM

Analysis Analyte Unit Cleanup Level

8270D SIM (PAH) 1-Methylnaphthalene ug/kg 410 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) 2-Methylnaphthalene ug/kg 1300 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Acenaphthene ug/kg 37000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Acenaphthylene ug/kg 18000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Anthracene ug/kg 390000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Benzo(a)Anthracene ug/kg 700 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Benzo[a]pyrene ug/kg 1500 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Benzo[b]Fluoranthene ug/kg 15000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Benzo[g,h,i]perylene ug/kg 2300000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Benzo[k]fluoranthene ug/kg 150000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Chrysene ug/kg 600000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Dibenzo[a,h]anthracene ug/kg 1500 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Fluoranthene ug/kg 590000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Fluorene ug/kg 36000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Indeno[1,2,3-c,d] pyrene ug/kg 15000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Naphthalene ug/kg 38 11.4 U 10.4 U 10.4 U 10.4 U 10.9 U 10.4 U

8270D SIM (PAH) Phenanthrene ug/kg 39000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

8270D SIM (PAH) Pyrene ug/kg 87000 14.3 U 12.9 U 13.1 U 12.9 U 13.7 U 13.0 U

AK101 Gasoline Range Organics mg/kg 300 2.15 UB 2.2 UB 2.14 UB 2.51 UB 2.67 UB 2.23 UB 2.51 UB

AK102 Diesel Range Organics mg/kg 250 41.3 10.4 U 16.7 J 15.6 J 10.9 U 39.2 J

AK103 Residual Range Organics mg/kg 11000 57.0 U 52.0 U 52.0 U 51.5 U 54.5 U 52.0 U

SM21 2540G Total Solids % N/A 87.3 95.6 94.9 95.9 90.4 95.4

SW8260D 1,1,1,2-Tetrachloroethane ug/kg 22 8.60 U 8.80 U 8.55 U 10.1 U 10.7 U 8.95 U 10.1 U

SW8260D 1,1,1-Trichloroethane ug/kg 32000 10.8 U 11.0 U 10.7 U 12.6 U 13.4 U 11.2 U 12.6 U

SW8260D 1,1,2,2-Tetrachloroethane ug/kg 3 0.860 U 0.880 U 0.855 U 1.00 U 1.07 U 0.895 U 1.00 U

SW8260D 1,1,2-Trichloroethane ug/kg 1.4 0.431 U 0.440 U 0.428 U 0.505 U 0.535 U 0.447 U 0.500 U

SW8260D 1,1-Dichloroethane ug/kg 92 10.8 U 11.0 U 10.7 U 12.6 U 13.4 U 11.2 U 12.6 U

SW8260D 1,1-Dichloroethene ug/kg 1200 10.8 U 11.0 U 10.7 U 12.6 U 13.4 U 11.2 U 12.6 U

SW8260D 1,1-Dichloropropene ug/kg 10.8 U 11.0 U 10.7 U 12.6 U 13.4 U 11.2 U 12.6 U

SW8260D 1,2,3-Trichlorobenzene ug/kg 150 43.1 U 44.0 U 42.8 U 50.5 U 53.5 U 44.6 U 50.0 U

SW8260D 1,2,3-Trichloropropane ug/kg 0.031 0.860 U 0.880 U 0.855 U 1.00 U 1.07 U 0.895 U 1.00 U

SW8260D 1,2,4-Trichlorobenzene ug/kg 82 10.8 U 11.0 U 10.7 U 12.6 U 13.4 U 11.2 U 12.6 U

SW8260D 1,2,4-Trimethylbenzene ug/kg 610 43.1 U 44.0 U 42.8 U 50.5 U 53.5 U 44.6 U 50.0 U

SW8260D 1,2-Dibromo-3-chloropropane ug/kg 43.1 U 44.0 U 42.8 U 50.5 U 53.5 U 44.6 U 50.0 U

SW8260D 1,2-Dibromoethane ug/kg 0.24 0.645 U 0.660 U 0.640 U 0.755 U 0.800 U 0.670 U 0.755 U

SW8260D 1,2-Dichlorobenzene ug/kg 2400 10.8 U 11.0 U 10.7 U 12.6 U 13.4 U 11.2 U 12.6 U

SW8260D 1,2-Dichloroethane ug/kg 5.5 0.860 U 0.880 U 0.855 U 1.00 U 1.07 U 0.895 U 1.00 U

SW8260D 1,2-Dichloropropane ug/kg 30 4.31 U 4.39 U 4.28 U 5.05 U 5.35 U 4.46 U 5.00 U

SW8260D 1,3,5-Trimethylbenzene ug/kg 660 10.8 U 11.0 U 10.7 U 12.6 U 13.4 U 11.2 U 12.6 U

Table A-1: Excavation Confirmation Sample Results

(Duplicate of UW-ESW-SS04)

UW-TB01

Description:

BLM Uranium 2

Lab Sample ID: 1224523001 1224523002 1224523003 1224523004 1224523005 1224523006 1224523010

Matrix: Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry weight) Soil/Solid (dry…