Wheatley_Reservoir_Sediment_Sampling_Report-June2026_-260817.pdf

15 June 2026

Keith Roumfort

Charles County Department of Public Works

1001 Radio Station Road

La Plata, Maryland 20646

Re:

Wheatley Lake Sediment Sampling

Charles County Wheatley Dam

La Plata, Maryland

Langan Project No.: 270088517

Dear Mr. Roumfort:

Langan Engineering and Environmental Services, LLC (Langan) has prepared this letter report for the Charles County Department of Public Works to document the results of sediment sampling completed on 23 April 2026 at the Charles County Wheatley Dam located in La Plata, Maryland

(the “site”). A Site Location Map is provided as Figure 1.

Langan understands that Charles County has proposed dredging activities within the reservoir for the Wheatley Dam. As such, the County requested Langan’s assistance in collecting and analyzing sediment samples from the reservoir bottom, the results of which are intended for use as input when considering reuse or disposal options for the dredging spoils.

The investigation scope and methods and results are provided herein.

INVESTIGATION SCOPE AND METHODS

On 23 April 2026, Langan collected eleven sediment samples (SED-1 through SED-11) from the reservoir bottom. The sample locations were evenly distributed in a grid pattern across the reservoir; sample locations are shown on Figure 2. The samples were collected using a Ponar grab sampler and screened for indications of environmental impacts such as staining, odors, or elevated photoionization detector (PID) readings. The samples were placed directly into laboratory-provided containers as wet samples (i.e. not decanted or dried).

The sediment samples were placed on ice in a cooler following collection and transported via

FedEx to Eurofins of Pensacola, Florida, a National Environmental Laboratory Accreditation

Program (NELAP)-accredited laboratory, under chain-of-custody procedures. Due to the age of the reservoir and unknown quality of the surface runoff entering the reservoir from the surrounding areas, the samples were analyzed for:

• Volatile organic compounds (VOC) by United States Environmental Protection Agency

(USEPA) Method 8260;

• Semi-volatile organic compounds (SVOC) by USEPA Method 8270;

• Total petroleum hydrocarbons (TPH) diesel range organics (DRO), gasoline range organics

(GRO), and oil range organics (ORO) by USEPA Method 8015;

La Plata, Maryland

Langan Project No.: 270088517

• Polychlorinated biphenyls (PCB) by USEPA Method 8082;

• Resource Conservation and Recovery Act (RCRA) list metals by USEPA Method 6020;

• Hexavalent chromium by USEPA Method 7196;

• Mercury by USEPA Method 7471;

• Pesticides by USEPA Method 8081;

• Herbicides by USEPA Method 8151;

• Dioxins by USEPA Method 8290;

• Sulfides by USEPA Method 9034 (SED-1, SED-3, SED-6, SED-9, and SED-11 only);

• Sulfates by USEPA Method 9038 (SED-1, SED-3, SED-6, SED-9, and SED-11 only);

• Per- and polyfluoroalkyl substances (PFAS) by USEPA Method 1633;

• Classification of soils for engineering purposes by ASTM International Method D2487

(SED-1, SED-3, SED-6, SED-9, and SED-11 only);

• Routine grainsize by ASTM International Method D422;

• Liquid limit, plastic limit, and plasticity index of soil by ASTM International Method D4318;

and

• Specific gravity of soil by D5550.

RESULTS

Sediment in the reservoir consists primarily of sandy silt with varying amounts of clay. All samples were non-plastic. Langan did not observe indications of environmental impacts such as staining, odors, or elevated PID readings in any of the sediment samples. The laboratory analytical report is provided in Attachment A. The sediment analytical results are summarized in Table 1 (chemical parameters) and Table 2 (physical parameters).

Langan completed a data usability review by evaluating quality control samples and parameters documented in the laboratory reports. Data qualifiers, if applicable, were applied to the analytical results based on the data review and are included in the results tables. A data verification worksheet is included in Attachment A. Data were found to be of acceptable quality for the project objectives.

The sediment sample results were compared to the Maryland Department of Environment (MDE)

Residential and Non-Residential Soil Cleanup Standards and the USEPA Region 3 Biological

Technical Assistance Group (BTAG) Freshwater Sediment Screening Benchmarks. Soil screening criteria were used assuming the sediment would be removed, allowed to drain back into the reservoir, and then disposed of accordingly. The results are summarized as follows:

• VOCs, TPH-GRO, hexavalent chromium, pesticides, herbicides, PFAS, and sulfide were not detected above the laboratory reporting limit in any of the samples.

• Dioxins and sulfate were detected above laboratory detection limits but below MDE and

USEPA standards.

• TPH detections included:

o TPH-DRO was detected in all 11 samples at concentrations ranging from 7.4 to 34 milligrams per kilogram (mg/kg), below the MDE Residential Soil Cleanup Standard of 230 mg/kg. The USEPA does not maintain BTAG Freshwater Sediment

La Plata, Maryland

Langan Project No.: 270088517

Screening Benchmarks for TPH.

o TPH-ORO was detected in all 11 samples at concentrations ranging from 4.5 to

44 mg/kg. MDE and the USEPA do not maintain standards for TPH-ORO.

• Metals detections included:

o Arsenic was detected in all 11 samples at concentrations ranging from 2.3 to 15 mg/kg, above MDE and USEPA standards. However, Maryland has established an anticipated background concentration (ATC) for arsenic in central Maryland of 4.9 mg/kg. Four samples (SED-5, SED-6, SED-7, and SED-9) exceeded the ATC.

o Cadmium was detected in all 11 samples at concentrations ranging from 0.96 to

2.8 mg/kg. 10 of the detections exceeded the BTAG Freshwater Sediment

Screening Benchmark of 0.99 mg/kg but were below the MDE Residential Soil

Cleanup Standard of 7.1 mg/kg.

o Selenium was detected in one sample (SED-11) at a concentration of 2.1 mg/kg.

The detection was above the BTAG Freshwater Sediment Screening Benchmark of 2 mg/kg, but below the MDE Residential Soil Cleanup Standard of 39 mg/kg.

o Three additional metals (barium, trivalent chromium, and lead) were detected at concentrations below the MDE and USEPA standards.

FINDINGS AND CONCLUSIONS

The sediment sample results indicate low-level exceedances of metals, including arsenic, cadmium, and selenium. The metals do not appear to be consistently detected at elevated levels across the site, and do not appear to be directly attributable to industrial operations. They are consistent with, and may be attributed to, historical agricultural use in the area. The detections indicate that the sediment may not be suitable for unrestricted reuse, but can be disposed of as non-hazardous waste in a permitted landfill facility.

Low levels of petroleum products, including diesel and oil range organics, were also detected.

Soils that have TPH concentrations above 10 mg/kg (i.e., the MDE’s treatment requirement for oil-contaminated soil treatment facilities) generally require disposal or treatment as petroleum-impacted material if removed for the site for disposal. While TPH was not detected at concentrations indicative of a release, it was detected at concentrations above 10 mg/kg in some locations, which may require additional coordination or consideration with the selected disposal facility.

DISCLAIMER

The environmental conditions that Langan interprets to exist between sampling points will differ from those that actually exist. The user of this report recognizes that actual conditions will vary from those encountered at the locations where sampling, surveys, observations or explorations are made by Langan and that the data, interpretation, and recommendations of Langan are based solely on the information available to it. Furthermore, the user of this report recognizes that passage of time, natural occurrences, and/or direct or indirect human intervention at or near the subject property may substantially alter discovered conditions. Langan shall not be responsible for interpretations by others of the information it develops or provides to the user of this report.

La Plata, Maryland

Langan Project No.: 270088517

CLOSING

We thank you for the opportunity to work with you on this project. Please contact us with any questions.

Sincerely, Langan Engineering and Environmental Services, LLC

Tess Reardon, PG

Project Geologist

Jeffrey Manuszak, PG

Associate Principal

Attachments

Figure 1 Site Location Map

Figure 2 Sample Location Map

Table 1 Summary of Sediment Analytical Results – Chemical Parameters

Table 2 Summary of Sediment Analytical Results – Physical Parameters

Attachment A Laboratory Analytical Reports

FIGURES

TABLES

Table 1

Summary of Sediment Analytical Results - Chemical Parameters

Charles County Wheatley Dam

La Plata, Maryland

Langan Project Number: 270088517

Sample Location: SED-1 SED-2 SED-3 SED-4 SED-5 SED-6 SED-7 SED-8 SED-9 SED-10 SED-11

Sample ID: SED-1_042326 SED-2_042326 SED-3_042326 SED-4_042326 SED-5_042326 SED-6_042326 SED-7_042326 SED-8_042326 SED-9_042326 SED-10_042326 SED-11_042326

Collection Date: 4/23/2026 4/23/2026 4/23/2026 4/23/2026 4/23/2026 4/23/2026 4/23/2026 4/23/2026 4/23/2026 4/23/2026 4/23/2026

Volatile Organic Compounds (mg/kg)

None detected

Semivolatile Organic Compounds (mg/kg)

Benzo(b)fluoranthene 1.1 21 0.0272 0.0042 J <1 <0.96 <1.1 <1.4 <1 <1.6 <0.83 <1.4 <0.78 0.0055 J

Diesel Range Organics 230 620 NS 9.9 J 8.4 J 13 J 34 16 J 7.4 J 25 12 J 20 10 J 33

Oil Range Organics NS NS NS 19 10 J 17 62 29 9.3 J 23 22 14 21 61

None detected

Arsenic 0.68 3 9.8 2.3 J 3.2 3.9 3.8 6.6 5.9 11 4.1 15 2.7 4.4

Barium 1,500 22,000 NS 93 130 120 140 210 150 250 91 230 81 130

Cadmium 7.1 98 0.99 1.8 2.1 1.8 2.6 2.7 1.6 2.8 1 J 2.5 1 0.96 J

Chromium, total NS NS 43.4 8.4 16 15 16 27 19 34 12 32 10 16

Chromium, trivalent 12,000 180,000 NS 8.4 16 15 16 27 19 34 12 32 10 16

Lead 400 800 35.8 9.8 16 14 17 26 19 30 9.9 31 8.6 14

Selenium 39 580 2 <5.4 <5.8 <5.9 <7.4 <8.6 <6.2 <9.5 <5.4 <8.5 <4.8 2.1 J

None detected

None detected

1,2,3,4,6,7,8-Heptachlorodibenzo-P-Dioxin (1,2,3,4,6,7,8-HpCDD) NS NS NS 230 200 170 270 180 160 290 130 320 98 130

1,2,3,4,6,7,8-Heptachlorodibenzofuran (1,2,3,4,6,7,8-HpCDF) NS NS NS 57 37 29 38 27 23 40 5.8 J 47 13 13 J

1,2,3,6,7,8-Hexachlorodibenzo-P-Dioxin (1,2,3,6,7,8-HxCDD) NS NS NS 9 J 6.2 J <15 <18 <21 <15 <23 <13 8.9 J <12 <19

1,2,3,7,8,9-Hexachlorodibenzo-P-Dioxin (1,2,3,7,8,9-HxCDD) NS NS NS 5.7 J <15 <15 <18 <21 <15 10 J <13 8.5 J <12 <19

Octachlorodibenzo-P-Dioxin (OCDD) NS NS NS 2,100 3,600 4,500 9,700 5,500 5,000 9,400 8,400 11,000 3,500 4,900

Octachlorodibenzofuran (OCDF) NS NS NS 170 120 84 110 69 56 99 14 J 95 31 32 J

Total Hexachlorodibenzo-P-Dioxin (Total HxCDD) NS NS NS 53 I 56 53 83 69 57 I 110 I 67 I 100 38 I 56 I

Total Hexachlorodibenzofuran (Total HxCDF) NS NS NS 7.7 J 6.3 J I <15 <18 <21 <15 <23 <13 <20 <12 <19

Total Heptachlorodibenzodioxins (Total HpCDD) NS NS NS 370 390 360 650 440 360 670 320 690 240 330

Total Heptachlorodibenzofurans (Total HpCDF) NS NS NS 200 140 90 130 85 65 I 120 I 16 130 34 34

Total Pentachlorodinzo-P-Dioxin (Total PeCDD) NS NS NS <13 9.1 J I <15 8.6 J I <21 7.9 J 18 J I <13 9.7 J <12 <19

Total Pentachlorodibenxofuran (Total PeCDF) NS NS NS 13 I <15 <15 <18 <21 <15 17 J I <13 <20 <12 <19

Total Tetrachlorodibenzo-P-Dioxin (Total TCDD) NS NS NS 2.3 J 2.6 J 2.3 J 4.9 I 2.3 J 1.7 J 8.2 I 0.6 J 1.4 J 1.2 J 2.9 J

Total Tetrachlorodibenzofurans (Total TCDF) NS NS NS 1.6 J 3 <2.9 2.9 J <4.2 <3.1 11 I <2.6 7.4 <2.4 <3.8

Sulfate (as SO4) NS NS NS <98 NA <100 NA NA <85 NA NA 42 J NA 36 J

Sulfide NS NS NS <79 NA <78 NA NA <77 NA NA <78 NA <77

None detected

Notes:

2. Table includes detected constituents only mg/kg = Milligrams per kilogram ng/kg = Nanograms per kilogram

NA = Not analyzed

NS = No standard

<0.20 = Not detected above laboratory reporting limit

I = Value is extimated maximum possible concentration (EMPC, dioxins only).

J = Result is less than the reporting limit but greater than or equal to the method detection limit and the concentration is an approximate value.

Red = Detection exceeds MDE Residential Soil Cleanup Standards

Bold = Detection exceeds MDE Non-Residential Soil Cleanup Standards

Underline = Detection exceeds USEPA Region 3 BTAG Benchmarks

Total Petroleum Hydrocarbons (mg/kg)

Metals (mg/kg)

Per- and Polyfluoroalkyl Substances (mg/kg)

MDE Non-Residential

Soil Cleanup

Standards

USEPA Region 3 BTAG MDE Residential Soil

Cleanup Standards

1. Sediment results were compared to Maryland Department of Environment (MDE) Residential and Non-Residential Soil Cleanup Standards (October 2018) and the United States Environmental Protection Agency (USEPA) Region 3 Biological

Technical Assistance Group (BTAG) Freshwater Sediment Screening Benchmarks (August 2006).

Polychlorinated Biphenyls (mg/kg)

Pesticides (mg/kg)

Herbicides (mg/kg)

Dioxins (ng/kg)

General Chemistry (mg/kg)

Table 2

Summary of Sediment Analytical Results - Physical Parameters

Charles County Wheatley Dam

La Plata, Maryland

Langan Project Number: 270088517

Sample Location: SED-1 SED-3 SED-6 SED-9 SED-11

Sample ID: SED-1_042326 SED-3_042326 SED-6_042326 SED-9_042326 SED-11_042326

Collection Date: 4/23/2026 4/23/2026 4/23/2026 4/23/2026 4/23/2026

Group Name Sandy Silt Sandy Silt Sandy Silt Sandy Silt Sandy Silt

Group Symbol ML ML ML ML ML

Percent Moisture 62.8 67.1 67.6 76.7 74.7

Gravel 0.5 0 0 0 0

Sand 45.1 34.1 2.7 2.2 15.7

Coarse Sand 0.7 0 0 0 0

Medium Sand 3.5 1.7 0.8 0.4 1.7

Fine Sand 40.9 32.4 1.9 1.8 14

Silt 50.7 55 83.2 76.3 77

Clay 3.7 10.9 14.1 21.5 7.3

Sieve Size 3 inch 100 100 100 100 100

50 mm (Sieve Size 2 inch) 100 100 100 100 100

37.5 mm (Sieve Size 1.5 inch) 100 100 100 100 100

25 mm (Sieve Size 1 inch) 100 100 100 100 100

19 mm (Sieve Size 0.75 inch) 100 100 100 100 100

9.5 mm (Sieve Size 0.375 inch) 100 100 100 100 100

4.75 mm (Sieve Size #4) 99.5 100 100 100 100

2 mm (Sieve Size #10) 98.8 100 100 100 100

0.85 mm (Sieve Size #20 96.9 99 99.4 99.6 98.6

0.425 mm (Sieve Size #40) 95.3 98.3 99.2 99.6 98.3

0.25 mm (Sieve Size #60) 93.7 96.2 98.8 99.4 97.2

0.18 mm (Sieve Size #80) 90.7 89.7 98.6 99.3 95.8

0.15 mm (Sieve Size #100) 85.7 83.5 98.4 99 93.6

0.075 mm (Sieve Size #200) 54.4 65.9 97.3 97.8 84.3

36.1 um (Hydrometer Reading 1) 17.6 27.3 50 75.7 38.5

22.9 um (Hydrometer Reading 2) 14.8 27.3 25.5 68.9 22.9

13.4 um (Hydrometer Reading 3) 9.3 20.8 20.6 43.5 16.7

9.8 um (Hydrometer Reading 4) 5.1 14.2 17.4 29.9 10.4

6.7 um (Hydrometer Reading 5) 3.7 10.9 14.1 21.5 7.3

3.3 um (Hydrometer Reading 6) 0.9 7.7 7.6 13 2.6

1.4 um (Hydrometer Reading 7) 0.9 4.4 4.3 11.3 1

Liquid Limit NP NP NP NP NP

Plastic Limit NP NP NP NP NP

Plasticity Index NP NP NP NP NP

Specific Gravity at 20 degrees Celsius 2.6 2.7 2.7 2.8 2.6

Notes:

g/cm3 = Grams per cubic centimeter mm = Millimeter

NP = Non-plastic um = Micrometer

Moisture (Percent)

Grainsize (Percent Finer)

NP = Non-plastic

Classification of Soils for Engineering Purposes

Grainsize (Percent)

Liquid Limit, Plastic Limit, and Plasticity Index of Soil

Specific Gravity (g/cm3)

ATTACHMENT A

LABORATORY ANALYTICAL REPORTS

Technical

Memorandum

1300 Wilson Boulevard Suite 450 Arlington, VA 22209-2323 T: 571.366.6800

Mailing Address: 1300 Wilson Boulevard Suite 450 Arlington, VA 22209-2323

To: Tim Arvin, Langan Project Engineer

From: Jackie Beam, Langan Staff Chemist

Date: May 19, 2026

Re: Data Usability Assessment

For Wheatley Lake, La Plata, Maryland

April 2026 Sediment Samples

This memorandum presents the findings of an analytical data validation from the analysis of sediment samples collected in April 2026 by Langan Engineering and Environmental Services at the Wheatley Lake site, located in La Plata, Maryland. The samples were analyzed by Eurofins

Pensacola (ISO/IEC 17025 registration # L2471) for volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), per- and polyfluoroalkyl substances (PFAS), herbicides, polychlorinated biphenyls (PCBs), pesticides, metals, hexavalent chromium, moisture, ash and organic matter, liquid limit, plastic limit and plasticity index of soils, specific gravity of soils by gas pycnometer, diesel range organics (DRO), dioxins and furans, sulfide and sulfate.

• VOCs by SW-846 Method 8260D

• SVOCs by SW-846 Method 8270DE

• PFAS by USEPA Method E1633

• Herbicides by SW-846 Method 8151A

• PCBs by SW-846 Method 8082A

• Pesticides by SW-846 Method 8081B

• Metals by SW-846 Methods 6010D/7471B

• Hexavalent Chromium by SW-846 Method 7196A

• Moisture, Ash and Organic matter by ASTM Method D2974

• Liquid Limit, Plastic Limit and Plasticity Index of Soils by ASTM Method D4318

• Specific Gravity of Soils by Gas Pycnometer by ASTM Method D5550

• Diesel Range Organics (DRO) by SW-846 Method 8015C

• Dioxins and Furans by SW-846 Method 8290A

• Sulfide by SW-846 Method 9034

• Sulfate by SW-846 Method 9038

Data Usability Assessment

For Wheatley Lake, La Plata, Maryland

April 2026 Sediment Samples

May 19, 2026 Page 2 of 5

Table 1, attached, summarizes the laboratory and client sample identification numbers, sample collection dates, and analytical parameters subject to review.

VALIDATION OVERVIEW

This data validation was performed in accordance with the following guidelines:

• USEPA Contract Laboratory Program “National Functional Guidelines for Organic Superfund

Methods Data Review” (EPA 540- R-20-005, November 2020)

• USEPA Contract Laboratory Program “National Functional Guidelines for Inorganic Superfund

Methods Data Review” (EPA 540- R-20-005, November 2020), and

• published analytical methodologies.

The following acronyms may be used in the discussion of data-quality issues:

%D Percent Difference MB Method Blank

CCV Continuing Calibration Verification MDL Method Detection Limit

FB Field Blank MS Matrix Spike

FD Field Duplicate MSD Matrix Spike Duplicate

ICAL Initial Calibration RF Response Factor

ICV Initial Calibration Verification RL Reporting Limit

ISTD Internal Standard RPD Relative Percent Difference

LCL Lower Control Limit RSD Relative Standard Deviation

LCS Laboratory Control Sample TB Trip Blank

LCSD Laboratory Control Sample Duplicate UCL Upper Control Limit

Tier 1 data validation is based on completeness and compliance checks of sample-related QC results including: sample receipt documentation; analytical holding times; sample preservation;

blank results (method, field, and trip); surrogate recoveries; MS/MSD recoveries and RPDs values; field duplicate RPDs, laboratory duplicate RPDs, and LCS/LCSD recoveries and RPDs. All sample delivery groups underwent Tier 1 validation review.

As a result of the review process, the following qualifiers may be assigned to the data in accordance with the USEPA guidelines and our best professional judgment:

R – The sample results are unusable. The results are rejected because of serious deficiencies in meeting quality control criteria in accordance with the applicable validation guidelines.

The analyte may or may not be present in the sample.

J – The analyte was positively identified above the quantitation limit, and the associated numerical value is the approximate concentration of the analyte in the sample.

Data Usability Assessment

For Wheatley Lake, La Plata, Maryland

April 2026 Sediment Samples

May 19, 2026 Page 3 of 5

UJ – The analyte was not detected at or above the quantitation limit. The reported quantitation limit may be imprecise because of potential low or indeterminate bias.

U – The analyte was not detected at or above the quantitation limit, or the analyte detection is impacted by blank contamination and qualified as non-detect in accordance with the applicable validation guidelines.

If any validation qualifiers are assigned, these qualifiers should supersede any laboratory-applied qualifiers. Data that is not qualified as a result of this data validation is considered acceptable on the basis of the items specified for review. Data that is qualified as “R” are considered invalid and are not technically usable for data interpretation. Data that is otherwise qualified because of minor data-quality anomalies are usable, as qualified in Table 2 (attached).

MAJOR DEFICIENCIES:

Major deficiencies include those that grossly impact data quality and necessitate the rejection of results. No major deficiencies were identified.

MINOR DEFICIENCIES:

Minor deficiencies include anomalies that directly impact data quality and necessitate qualification, but do not result in unusable data. The section below describes the minor deficiencies that were identified.

PFAs by SW-846 Method E1633

J293635-1

The LCS for batch 410-810738 exhibited a percent recovery below the LCL for 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (44%). The associated results in samples SED-

09_042326, SED-1_042326, SED-10_042326, SED-11_042326, SED-2_042326, SED-3_042326, SED-4_042326, SED-5_042326, SED-6_042326, SED-7_042326, and SED-8_042326 are qualified as UJ because of potential low bias.

Hexavalent Chromium by SW-846 Method 7196A

J293635-1

The MS/MSD performed on sample SED-1_042326 exhibited a percent recovery below the LCL for hexavalent chromium (0%). The associated results are qualified as UJ because of potential low bias.

Data Usability Assessment

For Wheatley Lake, La Plata, Maryland

April 2026 Sediment Samples

May 19, 2026 Page 4 of 5

OTHER DEFICIENCIES:

Other deficiencies include anomalies that do not directly impact data quality and do not necessitate qualification. The section below describes the other deficiencies that were identified.

VOCs by SW-846 Method 8260D

J293635-1

The LCS for batch 400-749236 exhibited percent recoveries above the UCL for chloroethane

(162%) and bromomethane (236%). The associated results are non-detect. No qualification is necessary.

The MS/MSD performed on sample SED-3_042326 exhibited a percent recovery above the UCL for bromomethane (167%, 153%). Organic results are not qualified on the basis of MS/MSD recoveries alone. No qualification is necessary.

SVOCs by SW-846 Method 8270E

J293635-1

The LCS for batch 400-747848 exhibited percent recoveries above the UCL for hexachlorobenzene (142%), bis(2-chloroethyl) ether (2-chloroethyl ether) (121%), hexachlorobutadiene (127%), hexachloroethane (133%), 2,4-dinitrotoluene (150%), 2,6-dinitrotoluene (174%), 2-chloronaphthalene (127%), 2-nitrophenol (158%), and 4-bromophenyl phenyl ether (136%). The associated results are non-detect. No qualification is necessary.

The LCS for batch 400-747857 exhibited a percent recovery above the UCL for pentachlorophenol

(154%). The associated results are non-detect. No qualification is necessary.

PCBs by SW-846 Method 8082A

J293635-1

The MS/MSD performed on sample SED-1_042326 exhibited RPDs outside of control limits for

PCB-1260 (aroclor 1260) (51%) and dalapon (58%). Organic results are not qualified on the basis of MS/MSD recoveries alone. No qualification is necessary.

FIELD DUPLICATE:

No field duplicates were collected.

Data Usability Assessment

For Wheatley Lake, La Plata, Maryland

April 2026 Sediment Samples

May 19, 2026 Page 5 of 5

CONCLUSION:

On the basis of this evaluation, the laboratory appears to have followed the specified analytical methods with the exception of errors discussed above. If a given fraction is not mentioned above, that means that all specified criteria were met for that parameter.

All data are considered usable, as qualified. In addition, completeness, defined as the percentage of analytical results that are judged to be valid, is 100%.

Signed:

Jackie Beam

Staff Chemist

Data Usability Assessment

For Wheatley Lake

April 2026 Sediment Samples

Table 1: Validator-Applied Qualification

SDG Client Sample ID Analysis Total (T) /

Dissolved (D) CAS # Analyte

Validator

Qualifier

J293635-1 SED-09_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-1_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-10_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-11_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-2_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-3_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-4_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-5_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-6_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-7_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-8_042326 E1633 T 763051-92-9

11-CHLOROEICOSAFLUORO-3-

OXAUNDECANE-1-SULFONIC ACID

UJ

J293635-1 SED-1_042326 SW7196A T 18540-29-9 CHROMIUM, HEXAVALENT UJ

ANALYTICAL REPORT

PREPARED FOR

Attn: Tess Reardon

Langan Engineering & Environmental Services LLC 1300 Wilson Boulevard, Suite 450 Arlington, Virginia 22209-2323

Generated 5/18/2026 9:10:29 AM

JOB DESCRIPTION

Wheatley Lake , MD

JOB NUMBER

400-293635-1

See page two for job notes and contact information.

Pensacola FL 32514 3355 McLemore Drive Eurofins Pensacola https://eol.et.eurofinsus.com/myEOL/

Eurofins Pensacola

Eurofins Pensacola is a laboratory within Eurofins Environment Testing Southeast, LLC, a company within Eurofins Environment Testing Group of Companies

Job Notes This report may not be reproduced except in full, and with written approval from the laboratory. The results relate only to the samples tested. For questions please contact the Project Manager at the e-mail address or telephone number listed on this page.

The test results in this report relate only to the samples as received by the laboratory and will meet all requirements of the methodology, with any exceptions noted. This report shall not be reproduced except in full, without the express written approval of the laboratory. All questions should be directed to the Eurofins Environment Testing Southeast, LLC Project Manager.

Authorization

Generated

5/18/2026 9:10:29 AM

Authorized for release by Mark Swafford, Project Manager II Mark.Swafford@et.eurofinsus.com (850)471-6207

Table of Contents

Client: Langan Engineering & Environmental Services LLC Project/Site: Wheatley Lake , MD

Laboratory Job ID: 400-293635-1

Cover Page

Table of Contents

Case Narrative

Detection Summary

Sample Summary

Client Sample Results

Definitions

QC Association

QC Sample Results

Chronicle

Method Summary

Certification Summary

Chain of Custody

Receipt Checklists

Job Narrative 400-293635-1

Receipt The samples were received on 4/25/2026 8:29 AM. Unless otherwise noted below, the samples arrived in good condition, and where required, properly preserved and on ice. The temperatures of the 4 coolers at receipt time were 0.7º C, 0.9º C, 1.5º C and 2.4º C.

GC/MS VOA

Method 8260D: The matrix spike / matrix spike duplicate (MS/MSD) recoveries for preparation batch 400-749236 and analytical batch 400-749189 were outside control limits for Bromomethane due to high bias for this analyte on this day of analysis.

Method 8260D: The continuing calibration verification (CCV) associated with batch 400-749189 recovered above the upper control limit for Bromomethane and Chloroethane. The samples associated with this CCV were non-detects for the affected analytes;

therefore, the data have been reported. The associated sample is:(CCVIS 400-749189/2).

Method 8260D: The continuing calibration verification (CCV) associated with batch 400-749189 recovered outside acceptance criteria, low biased, for 1,1,2,2-Tetrachloroethane and Acrylonitrile. A reporting limit (RL) standard was analyzed, and the target analytes are detected. Since the associated samples were non-detect for the analyte(s), the data are reported.

Method 8260D: The laboratory control sample (LCS) for preparation batch 400-749236 and analytical batch 400-749189 recovered outside control limits for the following analytes: Bromomethane and Chloroethane. These analytes were biased high in the LCS and were not detected in the associated samples; therefore, the data have been reported.

No additional analytical or quality issues were noted, other than those described above or in the Definitions/Glossary page.

GC/MS Semi VOA Method 8270E: The matrix spike / matrix spike duplicate (MS/MSD) recoveries for preparation batch 400-747848 and analytical batch 400-748278 were outside control limits for one or more analytes. See QC Sample Results for detail. Sample matrix interference and/or non-homogeneity are suspected because the associated laboratory control sample (LCS) recovery is within acceptance limits.

Method 8270E: The continuing calibration verification (CCV) associated with batch 400-748278 recovered above the upper control limit for 2,4-Dinitrotoluene, 2,6-Dinitrotoluene, 2-Nitrophenol and 4,6-Dinitro-2-methylphenol. The samples associated with this CCV were non-detects for the affected analytes; therefore, the data have been reported.

Method 8270E: The continuing calibration verification (CCV) associated with batch 400-748278 recovered outside acceptance criteria, low biased, for 4-Nitrophenol. A reporting limit (RL) standard was analyzed, and the target analytes are detected. Since the associated samples were non-detect for the analyte(s), the data are reported.

Method 8270E: Six surrogates are used for this analysis. The laboratory's SOP allows one of these surrogates to be outside acceptance criteria without performing re-extraction/re-analysis. The following sample contained an allowable number of surrogate compounds outside limits: (LCS 400-747848/2-A). These results have been reported and qualified.

Method 8270E: The laboratory control sample (LCS) for preparation batch 400-747848 and analytical batch 400-748278 recovered outside control limits for the following analytes: 2,4-Dinitrotoluene, 2,6-Dinitrotoluene, 2-Chloronaphthalene, 2-Nitrophenol, 4- Bromophenyl phenyl ether, Bis(2-chloroethyl)ether, Hexachlorobenzene, Hexachlorobutadiene and Hexachloroethane. These analytes were biased high in the LCS and were not detected in the associated samples; therefore, the data have been reported.

Method 8270E: The continuing calibration verification (CCV) associated with batch 400-748275 recovered outside acceptance criteria, low biased, for 4-Chlorophenyl phenyl ether, Benzo[k]fluoranthene, Hexachlorobenzene, Hexachlorocyclopentadiene and Indeno[1,2,3-cd]pyrene. A reporting limit (RL) standard was analyzed, and the target analytes are detected. Since the associated samples were non-detect for the analyte(s), the data are reported.

Method 8270E: The laboratory control sample (LCS) for preparation batch 400-747857 and analytical batch 400-748312 recovered outside control limits for the following analyte: Pentachlorophenol. This analyte was biased high in the LCS and was not detected in the associated samples; therefore, the data have been reported.

Method 8270E: The matrix spike / matrix spike duplicate (MS/MSD) recoveries for preparation batch 400-747857 and analytical batch 400-748312 were outside control limits for one or more analytes. See QC Sample Results for detail. Sample matrix interference and/or non-homogeneity are suspected because the associated laboratory control sample (LCS) recovery is within acceptance limits.

Case Narrative Client: Langan Engineering & Environmental Services LLC Job ID: 400-293635-1 Project: Wheatley Lake , MD

Eurofins Pensacola

Job ID: 400-293635-1 Eurofins Pensacola

Method 8270E: The continuing calibration verification (CCV) associated with batch 400-748429 recovered outside acceptance criteria, low biased, for 4-Bromophenyl phenyl ether, Benzo[g,h,i]perylene, Hexachlorocyclopentadiene and Indeno[1,2,3-cd]pyrene. A reporting limit (RL) standard was analyzed, and the target analytes are detected. Since the associated samples were non-detect for the analyte(s), the data are reported.

No additional analytical or quality issues were noted, other than those described above or in the Definitions/Glossary page.

GC VOA

No analytical or quality issues were noted, other than those described in the Definitions/Glossary page.

GC Semi VOA Method 8082A: The matrix spike / matrix spike duplicate / sample duplicate (MS/MSD/DUP) precision for preparation batch 400-747981 and analytical batch 400-748550 was outside control limits. Sample matrix interference and/or non-homogeneity are suspected because the associated laboratory control sample / laboratory control sample duplicate (LCS/LCSD) precision was within acceptance limits.

Method 8082A: The following samples were diluted due to the nature of the sample matrix: SED-1_042326 (400-293635-1), SED-2_042326 (400-293635-2), SED-3_042326 (400-293635-3), SED-4_042326 (400-293635-4), SED-5_042326 (400-293635-5), SED-6_042326 (400-293635-6), SED-7_042326 (400-293635-7), SED-8_042326 (400-293635-8), SED-10_042326 (400-293635-9), SED-09_042326 (400-293635-10), SED-11_042326 (400-293635-11), (400-293635-D-1-B MS) and (400-293635- D-1-C MSD). Elevated reporting limits (RLs) are provided.

Method 8015C: The matrix spike / matrix spike duplicate (MS/MSD) recoveries for preparation batch 400-748165 and analytical batch 400-748851 were outside control limits for one or more analytes. See QC Sample Results for detail. Sample matrix interference and/or non-homogeneity are suspected because the associated laboratory control sample (LCS) recovery is within acceptance limits.

Method 8081B: The continuing calibration verification (CCV) associated with batch 400-749501 recovered above the upper control limit for Aldrin, alpha-BHC, beta-BHC, delta-BHC, gamma-BHC (Lindane), cis-Chlordane, trans-Chlordane, 4,4'-DDD, 4,4'-DDE, 4,4'-DDT, Dieldrin, Endosulfan I, Endosulfan II, Endosulfan sulfate, Endrin, Endrin aldehyde, Endrin ketone, Heptachlor, Heptachlor epoxide and Methoxychlor. The samples associated with this CCV were non-detects for the affected analytes; therefore, the data have been reported.

Method 8081B: The following samples were diluted due to the nature of the sample matrix: SED-1_042326 (400-293635-1), SED-2_042326 (400-293635-2), SED-3_042326 (400-293635-3), SED-4_042326 (400-293635-4), SED-5_042326 (400-293635-5), SED-6_042326 (400-293635-6), SED-7_042326 (400-293635-7), SED-8_042326 (400-293635-8), SED-10_042326 (400-293635-9), SED-09_042326 (400-293635-10) and SED-11_042326 (400-293635-11). Elevated reporting limits (RLs) are provided.

Method 8151A: The following samples were diluted due to the nature of the sample matrix: SED-2_042326 (400-293635-2), SED-3_042326 (400-293635-3), SED-4_042326 (400-293635-4), SED-5_042326 (400-293635-5), SED-6_042326 (400-293635-6), SED-7_042326 (400-293635-7), SED-8_042326 (400-293635-8), SED-10_042326 (400-293635-9), SED-09_042326 (400-293635-10) and SED-11_042326 (400-293635-11). Elevated reporting limits (RLs) are provided.

No additional analytical or quality issues were noted, other than those described above or in the Definitions/Glossary page.

General Chemistry Method 7196A: The matrix spike / matrix spike duplicate (MS/MSD) recoveries for preparation batch 400-747827 and analytical batch 400-748184 were outside control limits. Sample matrix interference is suspected because the associated laboratory control sample (LCS) recovery was within acceptance limits.

Method 7196A: The method reporting limit check (MRL) for analytical batch 400-748184 recovered outside control limits for the following analytes: Cr (VI). These analytes were biased high in the MRL and were not detected in the associated samples;

therefore, the data have been reported.

No additional analytical or quality issues were noted, other than those described above or in the Definitions/Glossary page.

Case Narrative Client: Langan Engineering & Environmental Services LLC Job ID: 400-293635-1 Project: Wheatley Lake , MD

Eurofins Pensacola

Job ID: 400-293635-1 (Continued) Eurofins Pensacola

Detection Summary Job ID: 400-293635-1Client: Langan Engineering & Environmental Services LLC

Project/Site: Wheatley Lake , MD

Client Sample ID: SED-1_042326 Lab Sample ID: 400-293635-1

☼Benzo[b]fluoranthene

RL

0.88 mg/Kg

MDL

0.0037

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA1J0.0042 8270E

☼Diesel Range Organics [C10-C28] 13 mg/Kg5.3 Total/NA19.9 J 8015C

☼Oil Range Organics (C28-C35) 13 mg/Kg5.3 Total/NA119 8015C

☼1,2,3,4,6,7,8-HpCDD 13 ng/Kg5.2 Total/NA1230 8290A

☼1,2,3,4,6,7,8-HpCDF 13 ng/Kg5.2 Total/NA157 8290A

☼1,2,3,6,7,8-HxCDD 13 ng/Kg5.2 Total/NA19.0 J 8290A

☼1,2,3,7,8,9-HxCDD 13 ng/Kg5.2 Total/NA15.7 J 8290A

☼OCDD 39 ng/Kg34 Total/NA12100 8290A

☼OCDF 26 ng/Kg13 Total/NA1170 8290A

☼Total HxCDD 13 ng/Kg5.2 Total/NA153 I 8290A

☼Total HxCDF 13 ng/Kg5.2 Total/NA17.7 J 8290A

☼Total HpCDD 13 ng/Kg5.2 Total/NA1370 8290A

☼Total HpCDF 13 ng/Kg5.2 Total/NA1200 8290A

☼Total PeCDF 13 ng/Kg5.2 Total/NA113 I 8290A

☼Total TCDD 2.6 ng/Kg0.52 Total/NA12.3 J 8290A

☼Total TCDF 2.6 ng/Kg1.6 Total/NA11.6 J 8290A

☼Arsenic 2.7 mg/Kg0.84 Total/NA12.3 J 6010D

☼Barium 2.7 mg/Kg1.1 Total/NA193 6010D

☼Cadmium 1.1 mg/Kg0.35 Total/NA11.8 6010D

☼Chromium 2.7 mg/Kg0.89 Total/NA18.4 6010D

☼Lead 5.4 mg/Kg0.98 Total/NA19.8 6010D

Chromium, trivalent 5.0 mg/Kg0.37 Total/NA18.4 7196A

Group Name NONE Total/NA1Sandy Silt D2487

Group Symbol NONE Total/NA1ML D2487

Moisture Content % Total/NA1214.8 D2974

Liquid Limit NONE Total/NA1NP D4318

Plastic Limit NONE Total/NA1NP D4318

Plasticity Index NONE Total/NA1NP D4318

Specific Gravity at 20 deg Celsius g/cm3 Total/NA12.6 D5550

Sieve Size 3 inch - Percent Finer % Finer Total/NA1100.0 D7928/D6913

50 mm (Sieve Size 2 inch) % Finer Total/NA1100.0 D7928/D6913

37.5 mm (Sieve Size 1.5 inch) % Finer Total/NA1100.0 D7928/D6913

25 mm (Sieve Size 1 inch) % Finer Total/NA1100.0 D7928/D6913

19 mm (Sieve Size 0.75 inch) % Finer Total/NA1100.0 D7928/D6913

9.5 mm (Sieve Size 0.375 inch) % Finer Total/NA1100.0 D7928/D6913

4.75 mm (Sieve Size #4) % Finer Total/NA199.5 D7928/D6913

2 mm (Sieve Size #10) % Finer Total/NA198.8 D7928/D6913

0.85 mm (Sieve Size #20) % Finer Total/NA196.9 D7928/D6913

0.425 mm (Sieve Size #40) % Finer Total/NA195.3 D7928/D6913

0.25 mm (Sieve Size #60) % Finer Total/NA193.7 D7928/D6913

0.18 mm (Sieve Size #80) % Finer Total/NA190.7 D7928/D6913

0.15 mm (Sieve Size #100) % Finer Total/NA185.7 D7928/D6913

0.075 mm (Sieve Size #200) % Finer Total/NA154.4 D7928/D6913

36.1 um (Hydrometer Reading 1) % Finer Total/NA117.6 D7928/D6913

22.9 um (Hydrometer Reading 2) % Finer Total/NA114.8 D7928/D6913

13.4 um (Hydrometer Reading 3) % Finer Total/NA19.3 D7928/D6913

9.8 um (Hydrometer Reading 4) % Finer Total/NA15.1 D7928/D6913

6.7 um (Hydrometer Reading 5) % Finer Total/NA13.7 D7928/D6913

3.3 um (Hydrometer Reading 6) % Finer Total/NA10.9 D7928/D6913

1.4 um (Hydrometer Reading 7) % Finer Total/NA10.9 D7928/D6913

Clay % Total/NA13.7 D7928/D6913

Eurofins Pensacola

This Detection Summary does not include radiochemical test results.

Project/Site: Wheatley Lake , MD

Client Sample ID: SED-1_042326 (Continued) Lab Sample ID: 400-293635-1

Gravel

RL

MDLAnalyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA10.5 D7928/D6913

Coarse Sand % Total/NA10.7 D7928/D6913

Fine Sand % Total/NA140.9 D7928/D6913

Medium Sand % Total/NA13.5 D7928/D6913

Sand % Total/NA145.1 D7928/D6913

Silt % Total/NA150.7 D7928/D6913

Client Sample ID: SED-2_042326 Lab Sample ID: 400-293635-2

☼Diesel Range Organics [C10-C28]

RL

15 mg/Kg

MDL

6.1

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA1J8.4 8015C

☼Oil Range Organics (C28-C35) 15 mg/Kg6.1 Total/NA110 J 8015C

☼1,2,3,4,6,7,8-HpCDD 15 ng/Kg6.0 Total/NA1200 8290A

☼1,2,3,4,6,7,8-HpCDF 15 ng/Kg6.0 Total/NA137 8290A

☼1,2,3,6,7,8-HxCDD 15 ng/Kg6.0 Total/NA16.2 J 8290A

☼OCDD 45 ng/Kg39 Total/NA13600 8290A

☼OCDF 30 ng/Kg15 Total/NA1120 8290A

☼Total HxCDD 15 ng/Kg6.0 Total/NA156 8290A

☼Total HxCDF 15 ng/Kg6.0 Total/NA16.3 J I 8290A

☼Total HpCDD 15 ng/Kg6.0 Total/NA1390 8290A

☼Total HpCDF 15 ng/Kg6.0 Total/NA1140 8290A

☼Total PeCDD 15 ng/Kg6.0 Total/NA19.1 J I 8290A

☼Total TCDD 3.0 ng/Kg0.60 Total/NA12.6 J 8290A

☼Total TCDF 3.0 ng/Kg1.8 Total/NA13.0 8290A

☼Arsenic 2.9 mg/Kg0.91 Total/NA13.2 6010D

☼Barium 2.9 mg/Kg1.2 Total/NA1130 6010D

☼Cadmium 1.2 mg/Kg0.38 Total/NA12.1 6010D

☼Chromium 2.9 mg/Kg0.96 Total/NA116 6010D

☼Lead 5.8 mg/Kg1.1 Total/NA116 6010D

Chromium, trivalent 5.0 mg/Kg0.37 Total/NA116 7196A

Client Sample ID: SED-3_042326 Lab Sample ID: 400-293635-3

☼Diesel Range Organics [C10-C28]

RL

15 mg/Kg

MDL

6.0

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA1J13 8015C

☼Oil Range Organics (C28-C35) 15 mg/Kg6.0 Total/NA117 8015C

☼1,2,3,4,6,7,8-HpCDD 15 ng/Kg5.9 Total/NA1170 8290A

☼1,2,3,4,6,7,8-HpCDF 15 ng/Kg5.9 Total/NA129 8290A

☼OCDD 44 ng/Kg39 Total/NA14500 8290A

☼OCDF 29 ng/Kg15 Total/NA184 8290A

☼Total HxCDD 15 ng/Kg5.9 Total/NA153 8290A

☼Total HpCDD 15 ng/Kg5.9 Total/NA1360 8290A

☼Total HpCDF 15 ng/Kg5.9 Total/NA190 8290A

☼Total TCDD 2.9 ng/Kg0.59 Total/NA12.3 J 8290A

☼Arsenic 3.0 mg/Kg0.93 Total/NA13.9 6010D

☼Barium 3.0 mg/Kg1.2 Total/NA1120 6010D

☼Cadmium 1.2 mg/Kg0.39 Total/NA11.8 6010D

☼Chromium 3.0 mg/Kg0.98 Total/NA115 6010D

☼Lead 5.9 mg/Kg1.1 Total/NA114 6010D

Chromium, trivalent 5.0 mg/Kg0.37 Total/NA115 7196A

Group Name NONE Total/NA1Sandy Silt D2487

Group Symbol NONE Total/NA1ML D2487

Eurofins Pensacola

This Detection Summary does not include radiochemical test results.

Project/Site: Wheatley Lake , MD

Client Sample ID: SED-3_042326 (Continued) Lab Sample ID: 400-293635-3

Moisture Content

RL

MDLAnalyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA127.6 D2974

Liquid Limit NONE Total/NA1NP D4318

Plastic Limit NONE Total/NA1NP D4318

Plasticity Index NONE Total/NA1NP D4318

Specific Gravity at 20 deg Celsius g/cm3 Total/NA12.7 D5550

Sieve Size 3 inch - Percent Finer % Finer Total/NA1100.0 D7928/D6913

50 mm (Sieve Size 2 inch) % Finer Total/NA1100.0 D7928/D6913

37.5 mm (Sieve Size 1.5 inch) % Finer Total/NA1100.0 D7928/D6913

25 mm (Sieve Size 1 inch) % Finer Total/NA1100.0 D7928/D6913

19 mm (Sieve Size 0.75 inch) % Finer Total/NA1100.0 D7928/D6913

9.5 mm (Sieve Size 0.375 inch) % Finer Total/NA1100.0 D7928/D6913

4.75 mm (Sieve Size #4) % Finer Total/NA1100.0 D7928/D6913

2 mm (Sieve Size #10) % Finer Total/NA1100.0 D7928/D6913

0.85 mm (Sieve Size #20) % Finer Total/NA199.0 D7928/D6913

0.425 mm (Sieve Size #40) % Finer Total/NA198.3 D7928/D6913

0.25 mm (Sieve Size #60) % Finer Total/NA196.2 D7928/D6913

0.18 mm (Sieve Size #80) % Finer Total/NA189.7 D7928/D6913

0.15 mm (Sieve Size #100) % Finer Total/NA183.5 D7928/D6913

0.075 mm (Sieve Size #200) % Finer Total/NA165.9 D7928/D6913

36.1 um (Hydrometer Reading 1) % Finer Total/NA127.3 D7928/D6913

22.9 um (Hydrometer Reading 2) % Finer Total/NA127.3 D7928/D6913

13.4 um (Hydrometer Reading 3) % Finer Total/NA120.8 D7928/D6913

9.8 um (Hydrometer Reading 4) % Finer Total/NA114.2 D7928/D6913

6.7 um (Hydrometer Reading 5) % Finer Total/NA110.9 D7928/D6913

3.3 um (Hydrometer Reading 6) % Finer Total/NA17.7 D7928/D6913

1.4 um (Hydrometer Reading 7) % Finer Total/NA14.4 D7928/D6913

Clay % Total/NA110.9 D7928/D6913

Gravel % Total/NA10.0 D7928/D6913

Coarse Sand % Total/NA10.0 D7928/D6913

Fine Sand % Total/NA132.4 D7928/D6913

Medium Sand % Total/NA11.7 D7928/D6913

Sand % Total/NA134.1 D7928/D6913

Silt % Total/NA155.0 D7928/D6913

Client Sample ID: SED-4_042326 Lab Sample ID: 400-293635-4

☼Diesel Range Organics [C10-C28]

RL

18 mg/Kg

MDL

7.2

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA134 8015C

☼Oil Range Organics (C28-C35) 18 mg/Kg7.2 Total/NA162 8015C

☼1,2,3,4,6,7,8-HpCDD 18 ng/Kg7.2 Total/NA1270 8290A

☼1,2,3,4,6,7,8-HpCDF 18 ng/Kg7.2 Total/NA138 8290A

☼OCDD 54 ng/Kg47 Total/NA19700 8290A

☼OCDF 36 ng/Kg18 Total/NA1110 8290A

☼Total HxCDD 18 ng/Kg7.2 Total/NA183 8290A

☼Total HpCDD 18 ng/Kg7.2 Total/NA1650 8290A

☼Total HpCDF 18 ng/Kg7.2 Total/NA1130 8290A

☼Total PeCDD 18 ng/Kg7.2 Total/NA18.6 J I 8290A

☼Total TCDD 3.6 ng/Kg0.72 Total/NA14.9 I 8290A

☼Total TCDF 3.6 ng/Kg2.1 Total/NA12.9 J 8290A

☼Arsenic 3.7 mg/Kg1.2 Total/NA13.8 6010D

☼Barium 3.7 mg/Kg1.5 Total/NA1140 6010D

Eurofins Pensacola

This Detection Summary does not include radiochemical test results.

Project/Site: Wheatley Lake , MD

Client Sample ID: SED-4_042326 (Continued) Lab Sample ID: 400-293635-4

☼Cadmium

RL

1.5 mg/Kg

MDL

0.48

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA12.6 6010D

☼Chromium 3.7 mg/Kg1.2 Total/NA116 6010D

☼Lead 7.4 mg/Kg1.3 Total/NA117 6010D

Chromium, trivalent 5.0 mg/Kg0.37 Total/NA116 7196A

Client Sample ID: SED-5_042326 Lab Sample ID: 400-293635-5

☼Diesel Range Organics [C10-C28]

RL

21 mg/Kg

MDL

8.5

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA1J16 8015C

☼Oil Range Organics (C28-C35) 21 mg/Kg8.5 Total/NA129 8015C

☼1,2,3,4,6,7,8-HpCDD 21 ng/Kg8.4 Total/NA1180 8290A

☼1,2,3,4,6,7,8-HpCDF 21 ng/Kg8.4 Total/NA127 8290A

☼OCDD 63 ng/Kg56 Total/NA15500 8290A

☼OCDF 42 ng/Kg21 Total/NA169 8290A

☼Total HxCDD 21 ng/Kg8.4 Total/NA169 8290A

☼Total HpCDD 21 ng/Kg8.4 Total/NA1440 8290A

☼Total HpCDF 21 ng/Kg8.4 Total/NA185 8290A

☼Total TCDD 4.2 ng/Kg0.84 Total/NA12.3 J 8290A

☼Arsenic 4.3 mg/Kg1.3 Total/NA16.6 6010D

☼Barium 4.3 mg/Kg1.8 Total/NA1210 6010D

☼Cadmium 1.7 mg/Kg0.56 Total/NA12.7 6010D

☼Chromium 4.3 mg/Kg1.4 Total/NA127 6010D

☼Lead 8.6 mg/Kg1.6 Total/NA126 6010D

Chromium, trivalent 5.0 mg/Kg0.37 Total/NA127 7196A

Client Sample ID: SED-6_042326 Lab Sample ID: 400-293635-6

☼Diesel Range Organics [C10-C28]

RL

15 mg/Kg

MDL

6.1

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA1J7.4 8015C

☼Oil Range Organics (C28-C35) 15 mg/Kg6.1 Total/NA19.3 J 8015C

☼1,2,3,4,6,7,8-HpCDD 15 ng/Kg6.2 Total/NA1160 8290A

☼1,2,3,4,6,7,8-HpCDF 15 ng/Kg6.2 Total/NA123 8290A

☼OCDD 46 ng/Kg41 Total/NA15000 8290A

☼OCDF 31 ng/Kg15 Total/NA156 8290A

☼Total HxCDD 15 ng/Kg6.2 Total/NA157 I 8290A

☼Total HpCDD 15 ng/Kg6.2 Total/NA1360 8290A

☼Total HpCDF 15 ng/Kg6.2 Total/NA165 I 8290A

☼Total PeCDD 15 ng/Kg6.2 Total/NA17.9 J 8290A

☼Total TCDD 3.1 ng/Kg0.62 Total/NA11.7 J 8290A

☼Arsenic 3.1 mg/Kg0.96 Total/NA15.9 6010D

☼Barium 3.1 mg/Kg1.3 Total/NA1150 6010D

☼Cadmium 1.2 mg/Kg0.40 Total/NA11.6 6010D

☼Chromium 3.1 mg/Kg1.0 Total/NA119 6010D

☼Lead 6.2 mg/Kg1.1 Total/NA119 6010D

Chromium, trivalent 5.0 mg/Kg0.37 Total/NA119 7196A

Group Name NONE Total/NA1Sandy Silt D2487

Group Symbol NONE Total/NA1ML D2487

Moisture Content % Total/NA1354.8 D2974

Liquid Limit NONE Total/NA1NP D4318

Plastic Limit NONE Total/NA1NP D4318

Plasticity Index NONE Total/NA1NP D4318

Specific Gravity at 20 deg Celsius g/cm3 Total/NA12.7 D5550

Eurofins Pensacola

This Detection Summary does not include radiochemical test results.

Project/Site: Wheatley Lake , MD

Client Sample ID: SED-6_042326 (Continued) Lab Sample ID: 400-293635-6

Sieve Size 3 inch - Percent Finer

RL

% Finer

MDLAnalyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA1100.0 D7928/D6913

50 mm (Sieve Size 2 inch) % Finer Total/NA1100.0 D7928/D6913

37.5 mm (Sieve Size 1.5 inch) % Finer Total/NA1100.0 D7928/D6913

25 mm (Sieve Size 1 inch) % Finer Total/NA1100.0 D7928/D6913

19 mm (Sieve Size 0.75 inch) % Finer Total/NA1100.0 D7928/D6913

9.5 mm (Sieve Size 0.375 inch) % Finer Total/NA1100.0 D7928/D6913

4.75 mm (Sieve Size #4) % Finer Total/NA1100.0 D7928/D6913

2 mm (Sieve Size #10) % Finer Total/NA1100.0 D7928/D6913

0.85 mm (Sieve Size #20) % Finer Total/NA199.4 D7928/D6913

0.425 mm (Sieve Size #40) % Finer Total/NA199.2 D7928/D6913

0.25 mm (Sieve Size #60) % Finer Total/NA198.8 D7928/D6913

0.18 mm (Sieve Size #80) % Finer Total/NA198.6 D7928/D6913

0.15 mm (Sieve Size #100) % Finer Total/NA198.4 D7928/D6913

0.075 mm (Sieve Size #200) % Finer Total/NA197.3 D7928/D6913

36.1 um (Hydrometer Reading 1) % Finer Total/NA150.0 D7928/D6913

22.9 um (Hydrometer Reading 2) % Finer Total/NA125.5 D7928/D6913

13.4 um (Hydrometer Reading 3) % Finer Total/NA120.6 D7928/D6913

9.8 um (Hydrometer Reading 4) % Finer Total/NA117.4 D7928/D6913

6.7 um (Hydrometer Reading 5) % Finer Total/NA114.1 D7928/D6913

3.3 um (Hydrometer Reading 6) % Finer Total/NA17.6 D7928/D6913

1.4 um (Hydrometer Reading 7) % Finer Total/NA14.3 D7928/D6913

Clay % Total/NA114.1 D7928/D6913

Gravel % Total/NA10.0 D7928/D6913

Coarse Sand % Total/NA10.0 D7928/D6913

Fine Sand % Total/NA11.9 D7928/D6913

Medium Sand % Total/NA10.8 D7928/D6913

Sand % Total/NA12.7 D7928/D6913

Silt % Total/NA183.2 D7928/D6913

Client Sample ID: SED-7_042326 Lab Sample ID: 400-293635-7

☼Diesel Range Organics [C10-C28]

RL

23 mg/Kg

MDL

9.1

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA125 8015C

☼Oil Range Organics (C28-C35) 23 mg/Kg9.1 Total/NA123 8015C

☼1,2,3,4,6,7,8-HpCDD 23 ng/Kg9.4 Total/NA1290 8290A

☼1,2,3,4,6,7,8-HpCDF 23 ng/Kg9.4 Total/NA140 8290A

☼1,2,3,7,8,9-HxCDD 23 ng/Kg9.4 Total/NA110 J 8290A

☼OCDD 70 ng/Kg62 Total/NA19400 8290A

☼OCDF 47 ng/Kg23 Total/NA199 8290A

☼Total HxCDD 23 ng/Kg9.4 Total/NA1110 I 8290A

☼Total HpCDD 23 ng/Kg9.4 Total/NA1670 8290A

☼Total HpCDF 23 ng/Kg9.4 Total/NA1120 I 8290A

☼Total PeCDD 23 ng/Kg9.4 Total/NA118 J I 8290A

☼Total PeCDF 23 ng/Kg9.4 Total/NA117 J I 8290A

☼Total TCDD 4.7 ng/Kg0.94 Total/NA18.2 I 8290A

☼Total TCDF 4.7 ng/Kg2.8 Total/NA111 I 8290A

☼Arsenic 4.8 mg/Kg1.5 Total/NA111 6010D

☼Barium 4.8 mg/Kg2.0 Total/NA1250 6010D

☼Cadmium 1.9 mg/Kg0.62 Total/NA12.8 6010D

☼Chromium 4.8 mg/Kg1.6 Total/NA134 6010D

☼Lead 9.5 mg/Kg1.7 Total/NA130 6010D

Eurofins Pensacola

This Detection Summary does not include radiochemical test results.

Project/Site: Wheatley Lake , MD

Client Sample ID: SED-7_042326 (Continued) Lab Sample ID: 400-293635-7

Chromium, trivalent

RL

5.0 mg/Kg

MDL

0.37

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA134 7196A

Client Sample ID: SED-8_042326 Lab Sample ID: 400-293635-8

☼Diesel Range Organics [C10-C28]

RL

13 mg/Kg

MDL

5.2

Analyte Result Qualifier Unit Dil Fac D Method Prep Type

Total/NA1J12 8015C

☼Oil Range Organics (C28-C35) 13 mg/Kg5.2 Total/NA122 8015C

☼1,2,3,4,6,7,8-HpCDD 13 ng/Kg5.2 Total/NA1130 8290A

☼1,2,3,4,6,7,8-HpCDF 13 ng/Kg5.2 Total/NA15.8 J 8290A

☼OCDD 39 ng/Kg34 Total/NA18400 8290A

☼OCDF 26 ng/Kg13 Total/NA114 J 8290A

☼Total HxCDD 13 ng/Kg5.2 Total/NA167 I 8290A

☼Total HpCDD 13 ng/Kg5.2 Total/NA1320 8290A

☼Total HpCDF 13 ng/Kg5.2 Total/NA116 8290A

☼Total TCDD 2.6 ng/Kg0.52 Total/NA10.60 J 8290A

☼Arsenic 2.7 mg/Kg0.84 Total/NA14.1 6010D

☼Barium 2.7 mg/Kg1.1 Total/NA191 6010D

☼Cadmium 1.1 mg/Kg0.35 Total/NA11.0 J 6010D

☼Chromium 2.7 mg/Kg0.89 Total/NA112 6010D

☼Lead 5.4 mg/Kg0.98 Total/NA19.9 6010D

Chromium, trivalent 5.0 mg/Kg0.37 Total/NA112 7196A

Client Sample ID: SED-10_042326 Lab Sample ID: 400-293635-9

☼Diesel Range Organics [C10-C28]

RL

12 mg/Kg

MDL

4.8

Analyte Result Qualifier…