J_Former_Nike_Site_2024_Annual_Report.pdf

Installation Restoration ProgramInstallation Restoration Program

Former Nike Missile Site Groundwater Operable Unit 2024 Annual Operations and Performance Monitoring Letter Report (January – December 2024)

May 2025

U.S. Army Garrison

Aberdeen Proving Ground, Maryland

Distribution Restriction

Statement Approved for Public Release Distribution is Unlimited

# 250521-01

This Page Intentionally Left Blank.

Office

3417 Sunset Avenue

Ocean Township, NJ 07712

Phone: (732)-659-1000

Regional Office

1304 Governor Court

Suite 101

Abingdon, MD 21009

Phone: (410) 671-2970 www.ecc.net

20 May 2025

Mr. Rurik Loder

U.S. Army Garrison Aberdeen Proving Ground

Directorate of Public Works

ATTN: AMIM-APP-E

Aberdeen Proving Ground, Maryland 21005

Reference: Contract No. W56ZTN-17-D-0009

Delivery Order No. W56ZTN-21-F-0110

Subject: Former Nike Missile Site, Groundwater Operable Unit, 2024 Annual

Operations and Performance Monitoring Letter Report

Dear Mr. Loder:

Please find attached the Former Nike Missile Site, Groundwater Operable Unit, Annual Operations and Performance Monitoring Letter Report, for the period of 1 January through 31 December 2024. Work performed throughout 2024 included weekly deployment of sodium percarbonate filled permeable socks in three (3) injection wells, one (1) extraction well, and three (3) monitoring wells and quarterly sampling of select performance monitoring wells within the

Northern Boundary Area (NBA) and the Former Missile Maintenance Area

(MMA).

The treatment plant and extraction wells were disabled on 24 October 2013 in accordance with the Final 2015 Nike Explanation of Significant Differences

(ESD). In accordance with the 2015 ESD, the extraction system and plant infrastructure will be maintained if needed as a contingency.

Figure 1 displays the performance monitoring and treatment wells within the

NBA and Former MMA, as well as the monitoring wells within the Southeast

Area. The United States Environmental Protection Agency (USEPA) 2024 concurrence letter regarding the recommended additional sock treatments and optimization changes to the groundwater performance sampling is provided as

Attachment 1. The 2024 and historical data and operations information are included in the following attachments: the monthly operations reports containing the percarbonate sock treatment totals are provided as Attachment

2, the site-specific volatile organic compound (VOC) results and field forms from the quarterly sampling of the performance monitoring wells are included http://www.ecc.net/ as Attachment 3, and the Southeast Area VOC and monitored natural attenuation (MNA) historical results are provided as Attachment 4.

Sodium Percarbonate Sock Treatment

During 2024, sodium percarbonate socks were deployed weekly in treatment wells NMB100, W103, NMB22A, and NMB99 in the NBA, and in NMB-INJ-01, NMB-INJ-02, and NMB-INJ-03 in the

Former MMA (Figure 1). As a result of continued stable or increasing trends of trichloroethene (TCE) concentrations above site remedial goals, the USEPA recommended that wells NMB22A and NMB99 be treated with sodium percarbonate socks (Attachment 1). The approved treatment period (one calendar year) for wells NMB22A and NMB99 started on 18 March 2024.

The application of sodium percarbonate continues to provide localized treatment of residual TCE groundwater concentrations exceeding the maximum contaminant level (MCL) of 5 μg/L in wells

NMB22A, NMB99, W103, and NMB07B(R) and prevent offsite migration. Table 1 shows the total amount of sodium percarbonate, per well, introduced into the aquifer during 2024, as well as historical sodium percarbonate additions (12/2/16 through 12/31/24).

Note:

1 = Socks were deployed in extraction well W103 starting on 01/25/18. W103 will not be sampled during treatment.

2 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

Quarterly Groundwater Performance Monitoring in the NBA and Former MMA

The quarterly performance groundwater monitoring associated with the groundwater extraction and treatment was suspended in October 2013 and revised following a time critical removal action completed in 2014. Quarterly groundwater sampling for performance monitoring of the NBA and the

Former MMA has occurred from December 2014 to the present. The sampling has been conducted at nine (9) wells (W101, W102, NMB45B, NMB46B, NMB22A, NMB99, NMB62A, NMB07B(R), and

W107) to monitor compliance of five site-specific VOCs with their associated MCLs; and to monitor

VOC trends along the Installation boundary following groundwater treatment (Figure 1). TCE is the only VOC in groundwater that has exceeded the MCL. Per the USEPA approved optimization changes

Location

Total Sodium Percarbonate

Introduced (pounds)

Total Sodium Percarbonate

Introduced (pounds)

12/2/16 – 12/31/24

NMB100 372.8 3,295.8

NMB-INJ-01 101.4 646.5

NMB-INJ-02 103.6 659.9

NMB-INJ-03 101.2 651

NMB1031 1,225.8 6,597.2

NMB22A2 637.9 637.9

NMB992 159.2 159.2

Table 1 - 2024 and Historical Sodium Percarbonate Additions to the performance monitoring, wells NMB22A and NMB99 will be excluded from the quarterly sampling during sock treatment activities for one calendar year (treatment started in March 2024) and well NMB07B(R) will be sampled on an annual basis (started in December 2024) (Attachment 1). As a result of TCE concentrations being below the MCL since performance monitoring started in

December 2014 and below the detectable limit for three years, well W107 was removed from the monitoring program during 2023. Off-installation wells NMB53A and NMB55A were also sampled in

December 2024.

Table 2 summarizes the 2024 quarterly TCE results in the performance monitoring wells and the off-installation wells. Attachment 3 provides the VOC results from 2014 through 2024 as well as the 2024 field forms.

Laboratory and field quality control (QC) sampling was performed according to USEPA analytical data quality objectives. QC requirements for analyses were performed on all samples collected during the quarterly sampling events. The QC samples consisted of field duplicates and trip blanks. Advanced

Environmental Laboratory analyzed the groundwater and QC samples during the reporting period. No site-specific VOCs were detected in the trip blank samples and all duplicate samples were within required limits.

NBA Former

MMA Off-Installation

Sampling

Event

W101 W102 NMB22A1 NMB45B NMB46B NMB62A NMB991 NMB53A NMB55A NMB07B(R)

3/19/24 BQL BQL Treatment 1.1 4.6

BQL/BQL

(DUP)

Treatment NS NS NS

6/18/24 0.69 J 2.5 Treatment 1 4.2

BQL/BQL

(DUP)

Treatment NS NS NS

9/10/24 0.9 J 2.6 Treatment 1.2 4.2

BQL/BQL

(DUP)

Treatment NS NS NS

12/10/24 0.99 J 2.4 Treatment 1.3 4.4

BQL/BQL

(DUP)

Treatment 2.3 BQL 16

Note:

1 = NMB22A and NMB99 will be excluded from the quarterly sampling during sock treatment activities for one calendar year (treatment started in March 2024).

Results highlighted yellow exceed the MCL for TCE (5 μg/L)

BQL = below quantitation limit J = estimated value NS = not sampled

DUP = duplicate sample μg/L = micrograms per liter

The five NBA performance monitoring wells directly on the boundary (i.e., W101, W102, NMB45B, NMB46B, and NMB62A) showed a continuation of TCE concentrations below the MCL for 2024. Off-installation wells NMB53A and NMB55A were last sampled in 2013 and continue to show TCE concentrations below the MCL.

Figures 2 through 7 display the detected quarterly TCE results for all the NBA performance monitoring wells except NMB62A from December 2014 to December 2024. Figure 8 shows the detected TCE results for NMB53A from February 2011 to December 2024. The concentration plots also list the highest

TCE concentration detected at each well location in the upper right corner of the concentration plots.

Results from well NMB62A are not plotted because they have been consistently below the detection

Table 2 - Summary of 2024 Quarterly TCE Results (μg/L) limit since performance monitoring started in December 2014. Results from well NMB55A are also not plotted due to results being consistently below the detection limit.

TCE concentrations at NMB22A have ranged from 3.4 to 8.6 μg/L from 2014 through 2023, showing an overall stable trend to slightly reducing trend (Figure 2). TCE concentrations at well NMB99 have shown a slow steady increase from 0.85 μg/L in December 2014 to the highest detection of 8.4 μg/L occurring in December 2023 (Figure 3). Wells NMB22A and NMB99 were not sampled during 2024.

All the wells along the installation boundary sampled in 2024 continue to have TCE concentrations below analytical detection limit or below the MCL, with the exception of the 5.1 μg/L detection slightly above the MCL at monitoring well NMB46B during the second quarter 2021. Since December 2014, well W101 shows a stable linear trend (Figure 4) and well W102 shows a downward linear trend (Figure 5) in TCE concentrations. TCE concentrations at NMB45B have averaged 0.82 μg/L over the last ten years, showing a slight increasing linear trend (Figure 6). However, concentrations have remained below the

MCL. TCE concentrations at well NMB46B have ranged from 2.9 to 5.1 μg/L since 2014 (Figure 7), showing a slight increasing linear trend. However, TCE concentrations have remained stable below the

MCL since September 2021 (fourteen rounds of quarterly data), averaging 4.3 μg/L. Off-installation well

NMB53A has showed a stable linear trend in TCE concentrations since 2011, averaging 2.1 μg/L (Figure

8).

The oxygen reducing nature of the aquifer within the NBA only allows a very slow reduction of the TCE concentrations by dilution without a direct treatment method. Treatment with the sodium percarbonate socks supplies localized treatment within the area of the treated wells.

Within the Former MMA, the TCE concentration at well NMB07B(R) was 16 μg/L during December

2024. NMB07B(R) was only sampled once during 2024. Groundwater flow directions within the

NMB07B(R) area are suspected to be variable based on contaminant distribution and past water level measurements. Overall, TCE concentrations at NMB07B(R) appear to be slowly reducing over time.

Figure 9 displays the detected TCE concentrations at performance monitoring well NMB07B(R) between December 2014 and December 2024. Well NMB07B(R) continues to have the highest remaining concentrations of TCE within the Former Nike Site. TCE concentrations at NMB07B(R) ranged from 12 to 34 μg/L over the last ten years and continue to show a slow decreasing trend over time. The area of residual TCE groundwater contamination continues to be very localized in the vicinity of NMB07B(R).

Sodium percarbonate sock treatments at NMB-INJ-01, NMB-INJ-02, and NMB-INJ-03 only appear to impact the NMB07B(R) area during certain seasonal extremes, which cause the variable groundwater flow direction to move toward the south. Similar to the NBA, the oxygen reducing nature of the aquifer within the Former MMA only allows a very slow reduction of the TCE concentrations by dilution without a direct treatment method. Based on previous investigations within the area, the TCE contamination is located within the bottom of the unsaturated (vadose) zone and the top of the surficial aquifer. Significant clay content in the vadose zone may pose a challenge to reducing the residual TCE concentrations below the MCL.

Figure 10 displays the current Site TCE isocontour.

Groundwater Monitoring in the Southeast Area

The Southeast Area VOC and MNA sampling is conducted based on the 2005 ESD and was modified as per the 2015 ESD. The 2015 ESD indicated that once VOC concentrations have been below the MCLs for a period of two years then the sampling period would be reduced from annual to a five-year cycle.

VOC concentrations at the Southeast monitoring wells (NMB32A NMB36, NMB52A, NMB96B, and

NMB97B) have been below the MCLs from 2018 through 2022. Sampling was not conducted during this reporting period. The next five-year sampling event would occur in spring 2026.

Table 3 provides a summary of the TCE results for the Southeast Area wells from 2017 through 2022.

The historical VOC and MNA results are provided in Attachment 4.

Results highlighted yellow exceed the MCL for TCE (5 μg/L)

BQL = below quantitation limit

J = estimated value μg/L = micrograms per liter

From the data provided in Attachment 4, TCE is the only VOC detected from 2014 to 2022 that exceeded the MCL (5 μg/L) and only in monitoring well NMB52B. TCE sampling results from 2017 to 2022

(Table 3) indicate that TCE was last detected at the MCL at NMB52B in April 2017. TCE concentrations at NMB52B have been below the MCL from 2018 through 2022.

Within the Southeast Area, microbial activity is conducive to the downward trend in TCE concentrations through natural attenuation. These indicators are evidence that reductive, anaerobic dechlorination occurs in this portion of the surficial aquifer. However, the degradation of the remaining residual low levels of

TCE appears to have slowed or stalled. The presence of dissolved oxygen (DO) and carbon dioxide (CO2) indicate aerobic metabolism, whose byproducts diminishes the effectiveness of the more desired anaerobic reductive dechlorination pathway. Despite the less favorable anaerobic conditions, TCE contamination at well NMB52B continues to slowly decline most likely due to natural processes such as dilution.

Sample Date NMB32A NMB36A NMB52B NMB96B NMB97B

April 2017 BQL 1.4 5 1.4 1.8

April 2018 BQL 1.6 4.4 1.1 1.3

April 2019 BQL 1.2 1.8 1.2 1.2

June 2020 BQL 1.3 3.1 0.82 J 1.2

March-April 2022 BQL 1.1 1.9 BQL 0.86 J

Table 3 – Summary of Southeast Area TCE Results (μg/L) (2017-2022)

Conclusions and Recommendations

Northern Boundary Area (NBA)

Based on results of TCE concentrations still at or above the MCL, sodium percarbonate sock treatments at W103 and NMB100 will continue in the NBA. The sock treatment period for wells NMB22A and

NMB99 will continue until March 2025.

Quarterly groundwater sampling for site specific VOCs will continue at wells W101, W102, NMB45B, NMB46B, and NMB62A to monitor the status of VOC contaminants in groundwater adjacent to the installation boundary. Quarterly sampling at wells NMB22A and NMB99 will resume after the treatment period is completed in March 2025.

Off-installation wells NMB53A and NMB55A will be sampled for site specific VOCs on a five-year cycle.

A groundwater elevation evaluation of the NBA will be included with the annual reports starting in 2025.

Former Missile Maintenance Area (MMA)

With TCE concentrations still above the MCL, sodium percarbonate sock treatments at NMB-INJ-01, NMB-INJ-02, and NMB-INJ-03 will continue in the area to allow treatment of the area north of

NMB07B(R).

Sampling for site specific VOCs will continue annually until VOC concentrations meet the remedial goals.

Southeast Area

Sampling conducted between 2018 and 2022 in the Southeast Area indicated that VOC concentrations at the five (5) monitoring locations (NMB32A NMB36, NMB52A, NMB96B, and NMB97B) have met remedial goals.

Sampling of the five (5) monitoring wells will continue on a five-year basis for site-specific VOCs and groundwater analysis for the MNA parameters will be removed from future sampling events

(Attachment 1). The next Southeast Area five-year sampling is tentatively scheduled for 2026.

Please contact me at (410) 671-2970 should you have any questions or concerns regarding this data report.

Sincerely, Helen Cavanagh

ECC

cc: Jen Schaefer and Rob Wasserman, ECC

FIGURES

Figure 2

Former Nike Missile Site Northern Boundary Area

Monitoring Well NMB22A

Quarterly Trichloroethene (TCE) Results (2014-2024)

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Note - Data in the chart is from NMB61A until September 2015. When sock treatments were resumed at NMB61A, well NMB22A was added to the quarterly monitoring.

Data in the chart is from NMB22A starting in December 2015 to September 2023. Treatment socks were deployed in well NMB22A starting on 3/18/2024. NMB22A will be treated for a period of one calendar year and not be sampled during treatment.

Maximum detected concentration of TCE at well NMB61A was 10 µg/L during the treatment plant quarterly monitoring program in February 2011 and TCE at well NMB22A was 12.7 µg/L during the Pre-design Investigation sampling

Figure 3

Monitoring Well NMB99

Quarterly Trichloroethene (TCE) Results (2014-2024)

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Maximum detected concentration of TCE at well NMB99 is 8.4 µg/L during the current quarterly monitoring program in December 2024

Note - Treatment socks were deployed in well NMB99 starting on 3/18/2024. NMB99 will be treated for a period of one calender year and not be sampled during treatment.

Figure 4

Extraction Well W101

Quarterly Trichloroethene (TCE) Results (2014-2024)

Note - Data in the chart that were below the method detection limit are plotted at 0.2 µg/L

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Maximum detected concentration of TCE at well W101 was 2 µg/L during the treatment plant quarterly monitoring program in August 2001

Figure 5

Extraction Well W102

Quarterly Trichloroethene (TCE) Results (2014-2024)

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Note - Data in the chart that were below the method detection limit are are plotted at 0.2 µg/L

Maximum detected concentration of TCE at well W102 was 4.1 µg/L during the treatment plant quarterly monitoring program in August 2008

Figure 6

Monitoring Well NMB45B

Quarterly Trichloroethene (TCE) Results (2014-2024)

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Maximum detected concentration of TCE at well NMB45B was 18 µg/L during the pre-design investigation sampling in September 1996

Figure 7

Monitoring Well NMB46B

Quarterly Trichloroethene (TCE) Results (2014-2024)

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Maximum detected concentration of TCE at well NMB46B was 19.7 µg/L during the Pre-Design Investigation Sampling in September 1996

Figure 8

Monitoring Well NMB53A

Trichloroethene (TCE) Detections (2011-2024)

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TC

E

C o n ce n tr at io n µ g/

L)

Date

TCE

Linear (TCE)

Linear (Remedial Goal)

Maximum detected concentration of TCE at well NMB53A was 2.6 µg/L during the sampling event in June 2012

Figure 9 Former Nike Missile Site Missile Maintenance Area Monitoring

Well NMB07B(R)

Quarterly Trichloroethene (TCE) Results (2014-2024)

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TC

E

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TCE

Linear (TCE)

Linear (Remedial Goal)

Maximum detected concentration of TCE at well NMB07B was 270 µg/L during a plume migration study in June 1999

NMB-INJ-01

NS

NMB100

NS

NMB-INJ-03

NS

NMB-INJ-02

NS

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary

W101

0.99 J (Dec 2024)

W103

8.8 (Dec 2017)

NMB03A

NS

NMB61A

NS

NMB53A

2.3 (Dec 2024)

NMB55A

BQL (Dec 2024)

W102

2.4 (Dec 2024)

W108

NS

W107

NS

W106

NS

W105

NS

W104

NS

NMB07B(R)

16 (Dec 2024)

NMB52B

1.9 (Mar-Apr 2022)

NMB99

8.4 (Dec 2023)

NMB45B

1.3 (Dec 2024)

NMB22A

5.0 (Dec 2023)

NMB62A

BQL (Dec 2024)

NMB46B

4.4 (Dec 2024)

NMB36A

1.1 (Mar-Apr 2022)

NMB32A

BQL (Mar-Apr 2022)

NMB96B

BQL (Mar-Apr 2022)

NMB97B

0.86 J (Mar-Apr 2022)

Legend

Monitoring Well

Extraction Well

Injection Well

TCE > 5 µg/L Inferred Isocontour

Installation/LUCs Boundary

Buildings

Paving

Streams

Wetland

0 200 400100

Feet

Map Area

Key Map

E C

C G

IS

S er ve r G

:\P ro je ct s\ A be rd ee n\

P ro

\N ik e\ Y r2

4\ N ik e_

Y r2

4.

ap rx

Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

FIGURE 10

Former

Nike Missile Site TCE Isocontour Map

Notes:

1. TCE = Trichloroethene

2. All the TCE results are in µg/L

Sample dates are in parentheses.

NS = Not Sampled BQL = below quantitative limit J = estimated value Red font indicates >= 5 µg/L.

General groundwater flow direction

General groundwater flow direction

NMB-INJ-01

NS

NMB-INJ-03

NS

NMB-INJ-02

NS

NMB07B(R)

16 (Dec 2024)

Former Missile Maintenance Area

(Inset Map)

ATTACHMENT 1

Mr. Rurik Loder Acting Chief Environmental Restoration Branch Directorate of Public Works Aberdeen Proving Ground, Maryland

Re: Changes to the Former Nike Missile Battery Site, Groundwater Operable Unit, Operations and Performance Monitoring

Dear Mr. Loder, The U.S. Environmental Protection Agency (EPA) Region 3 has reviewed the proposed changes to the operations and performance monitoring at the Former Nike Missile Battery Site, Groundwater Operable Unit, outlined in the letter dated January 26, 2024. EPA concurs with the proposed performance optimization changes for the Northern Boundary Area, the reduction in monitoring frequency from quarterly to annually at the Former Missile Maintenance Area, and the continued site-specific VOC sampling on a five-year basis at the Southeast Area as stated in the above referenced letter.

Should you have any question, please contact me at barbieri.andrea@epa.gov

Sincerely, Andrea Barbieri Remedial Project Manager US EPA Region 3

ANDREA BARBIERI

Digitally signed by ANDREA

BARBIERI

Date: 2024.03.01 13:07:53 -05'00'

ATTACHMENT 2

Report No. 741

FORMER NIKE MISSILE BATTERY

GROUNDWATER TREATMENT FACILITY

MONTHLY STATUS REPORT

Month: January 2024

Reporting Period: 1/1/2024 – 1/31/2024

I. SYSTEM OPERATION AND MAINTENANCE SUMMARY

The plant and extraction wells have been disabled since 10/24/13 in accordance with the Final Nike

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained and remain in standby status if the need arises for system reactivation.

The weekly inspections were completed on 1/4/24, 1/11/24, 1/18/24, and 1/25/24.

Below are the sampling results from the fourth quarter 2023 and attached is a location map. The next quarterly sampling event is scheduled for March 2024.

Q4 2023 Results:

Former Missile Maintenance Area

Analyte (µg/L)

EPA

MCL

(µg/L)

NMB07B(R)

cis-1,2-Dichloroethene 70 0.99 J

Tetrachloroethene 5 BQL trans-1,2-Dichloroethene 100 BQL

Trichloroethene 5 19

Vinyl chloride 2 BQL

Northern Boundary

EPA

MCL

(µg/L)

W101 W102 NMB22A NMB45B NMB46B NMB62A NMB99

cis-1,2-Dichloroethene 70 1.6 J BQL 6.7 2.1 6.8 BQL 20

Tetrachloroethene 5 BQL BQL BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL BQL BQL

Trichloroethene 5 1.1 0.46 J 5 1.3 4.4 BQL 8.4

Vinyl chloride 2 BQL BQL BQL BQL BQL BQL BQL

Note:

Results highlighted yellow exceed the MCL

BQL = below quantitation limit µg/L = micrograms per liter

Report No. 741

Sodium percarbonate socks were deployed four times in treatment wells NMB-INJ-01, NMB-INJ-02, NMB-INJ-03, NMB100, and in extraction well W103. The application of sodium percarbonate will continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

NMB07B(R), NMB22A, NMB99, and W103 and prevent offsite migration.

Below are the total amounts of sodium percarbonate introduced to the treatment wells during January and from 12/2/16 through 1/31/24.

Introduced (pounds)

January 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-1/31/24

NMB100 34.2 2,957.2

NMB-INJ-01 7.4 552.5

NMB-INJ-02 7.2 563.5

NMB-INJ-03 7 556.8

W103* 96.2 5,467.6

Note:

* = Socks were deployed in extraction well W103 starting on 01/25/18. W103 will not be sampled during treatment.

With TCE concentrations stable at NMB22A and slowly increasing at NMB99, USEPA recommended treating those two wells with sodium percarbonate socks and continue monitoring the wells adjacent to the boundary. A letter documenting the recommended additional sock treatments and optimization changes to the groundwater performance sampling was submitted to the regulators on 30 January 2024.

The letter also documented the following proposed changes to the performance monitoring program as discussed during the October 2023 Tier I meeting:

• Reduce sampling from quarterly to annually for NMB07B(R) due to the slow, steady decline of

TCE concentrations.

• Removal of monitored natural attenuation analyses from the 5-year sampling event for the

Southeast Area monitoring wells. The wells will continue to be sampled for site-specific VOCs on the 5-year schedule.

• Wells NMB22A and NMB99 will be excluded from the quarterly sampling in the Northern

Boundary Area during sock treatment activities.

Following written concurrence from USEPA, the proposed sock treatment activities and changes to the monitoring program will be implemented. Documentation of all treatment and sampling activities will continue to be provided in the monthly and annual reports.

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NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Performance Monitoring Wells

Report No. 742

FORMER NIKE MISSILE BATTERY

GROUNDWATER TREATMENT FACILITY

MONTHLY STATUS REPORT

Month: February 2024

Reporting Period: 2/1/2024 – 2/29/2024

I. SYSTEM OPERATION AND MAINTENANCE SUMMARY

The plant and extraction wells have been disabled since 10/24/13 in accordance with the Final Nike

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained and remain in standby status if the need arises for system reactivation.

The weekly inspections were completed on 2/1/24, 2/8/24, 2/15/24, 2/22/24, and 2/29/24.

Below are the sampling results from the fourth quarter 2023 and attached is a location map. The next quarterly sampling event is scheduled for March 2024.

Q4 2023 Results:

Former Missile Maintenance Area

Analyte (µg/L)

EPA

MCL

(µg/L)

NMB07B(R)

cis-1,2-Dichloroethene 70 0.99 J

Tetrachloroethene 5 BQL trans-1,2-Dichloroethene 100 BQL

Trichloroethene 5 19

Vinyl chloride 2 BQL

Northern Boundary

Analyte (µg/L)

EPA

MCL

(µg/L)

W101 W102 NMB22A NMB45B NMB46B NMB62A NMB99

cis-1,2-Dichloroethene 70 1.6 J BQL 6.7 2.1 6.8 BQL 20

Tetrachloroethene 5 BQL BQL BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL BQL BQL

Trichloroethene 5 1.1 0.46 J 5 1.3 4.4 BQL 8.4

Vinyl chloride 2 BQL BQL BQL BQL BQL BQL BQL

Note:

Results highlighted yellow exceed the MCL

BQL = below quantitation limit

Report No. 742

Sodium percarbonate socks were deployed five times in treatment wells NMB-INJ-01, NMB-INJ-02, NMB-INJ-03, NMB100, and in extraction well W103. The application of sodium percarbonate will continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

Below are the total amounts of sodium percarbonate introduced to the treatment wells during February and from 12/2/16 through 2/29/24.

Introduced (pounds)

February 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-2/29/24

NMB100 40.2 2,997.4

NMB-INJ-01 8.8 561.3

NMB-INJ-02 8.8 572.3

NMB-INJ-03 9.2 566

W103* 120.6 5,588.2

Note:

* = Socks were deployed in extraction well W103 starting on 01/25/18. W103 will not be

USEPA approved the proposed optimization changes to the performance monitoring and additional sock treatments on 1 March 2024. The following recommendations will be implemented:

• Wells NMB22A and NMB99 will be treated weekly with sodium percarbonate socks for a period of one calendar year starting in March 2024 and the wells will be excluded from the quarterly sampling during sock treatment activities;

• Well NMB07B(R) sampling frequency will be reduced from quarterly to annually; and

• The monitored natural attenuation analyses will be removed from the 5-year sampling event for the Southeast Area monitoring wells. The wells will continue to be sampled for site-specific

VOCs on the 5-year schedule.

Documentation of all treatment and sampling activities will continue to be provided in the monthly and annual reports.

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NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 743

Month: March 2024

Reporting Period: 3/1/2024 – 3/31/2024

I. SYSTEM OPERATION AND MAINTENANCE SUMMARY

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained

The weekly inspections were completed on 3/7/24, 3/13/24, 3/20/24, and 3/28/24.

The first quarter 2024 sampling event was conducted on 3/19/24 (below are the results and attached is a location map). Samples were collected from two extraction wells (W101, W102) and three monitoring wells (NMB45B, NMB46B, NMB62A). Per the USEPA approved optimization changes to the performance monitoring, wells NMB22A and NMB99 will be excluded from the quarterly sampling during sock treatment activities for one calendar year and well NMB07BR will be sampled on an annual basis starting in December 2024.

There were no VOC concentrations reported above the MCLs during this round of sampling. The next quarterly sampling event is scheduled for June 2024.

Q1 2024 Results:

Northern Boundary

EPA

MCL

(µg/L)

W101 W102 NMB45B NMB46B NMB62A

cis-1,2-Dichloroethene 70 0.61 J BQL 1.4 J 6.4 BQL

Tetrachloroethene 5 BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL

Trichloroethene 5 BQL BQL 1.1 4.6 BQL

Vinyl chloride 2 BQL BQL BQL BQL BQL

Note:

BQL = below quantitation limit

Report No. 743

Sodium percarbonate socks were deployed four times in treatment wells NMB-INJ-01, NMB-INJ-02, NMB-INJ-03, NMB100, and in extraction well W103 and two times in wells NMB22A and NMB99. The application of sodium percarbonate will continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells NMB07B(R), NMB22A, NMB99, and W103 and prevent offsite migration.

Below are the total amounts of sodium percarbonate introduced to the treatment wells during March and from 12/2/16 through 3/31/24.

Introduced (pounds)

March 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-3/31/24

NMB22A1 31.4 31.4

NMB991 7.6 7.6

NMB100 32.4 3,029.8

NMB-INJ-01 8 569.3

NMB-INJ-02 8.2 580.5

NMB-INJ-03 7.4 573.4

W1032 98.4 5,686.6

Note:

1 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and

NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

2 = Socks were deployed in extraction well W103 starting on 01/25/18. W103 will not be

Documentation of all treatment and sampling activities will continue to be provided in the monthly and

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NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 744

Month: April 2024 Reporting Period: 4/1/2024 – 4/30/2024

System Operation and Maintenance Summary:

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained

The weekly inspections were completed on 4/4/24, 4/11/24, 4/18/24, and 4/25/24.

Sampling and Treatment Activities:

Below are the sampling results from the first quarter 2024 and attached is a location map. The next

Northern Boundary (Q1 2024 Groundwater Results)

MCL

(µg/L)

W101 W102 NMB45B NMB46B NMB62A

cis-1,2-Dichloroethene 70 0.61 J BQL 1.4 J 6.4 BQL Tetrachloroethene 5 BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL Trichloroethene 5 BQL BQL 1.1 4.6 BQL Vinyl chloride 2 BQL BQL BQL BQL BQL

Note:

BQL = below quantitation limit

Sodium percarbonate socks were deployed four times in treatment wells: NMB22A, NMB99, NMB100, NMB-INJ-01, NMB-INJ-02, NMB-INJ-03, and W103. The application of sodium percarbonate will continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

Report No. 744

Below are the total amounts of sodium percarbonate introduced to the treatment wells during April and from 12/2/16 through 4/30/24.

Introduced (pounds) April 2024

Total Sodium Percarbonate Introduced (pounds)

12/2/16-4/30/24

NMB22A1 64.2 95.6

NMB991 15.8 23.4

NMB100 32.8 3,062.6

NMB-INJ-01 7.8 577.1

NMB-INJ-02 7.6 588.1

NMB-INJ-03 7.8 581.2

W1032 97.2 5,783.8 Note:

1 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

Documentation of all treatment and sampling activities will continue to be provided in the monthly and

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NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 745

Month: May 2024

Reporting Period: 5/1/2024 – 5/31/2024

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained

The weekly inspections were completed on 5/2/24, 5/9/24, 5/15/24, 5/23/24, and 5/29/24.

Below are the sampling results from the first quarter 2024 and attached is a location map. The next

Northern Boundary (Q1 2024 Groundwater Results)

MCL

(µg/L)

W101 W102 NMB45B NMB46B NMB62A

cis-1,2-Dichloroethene 70 0.61 J BQL 1.4 J 6.4 BQL

Tetrachloroethene 5 BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL

Trichloroethene 5 BQL BQL 1.1 4.6 BQL

Vinyl chloride 2 BQL BQL BQL BQL BQL

Note:

BQL = below quantitation limit continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

Report No. 745

Below are the total amounts of sodium percarbonate introduced to the treatment wells during May and from 12/2/16 through 5/31/24.

Introduced (pounds)

May 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-5/31/24

NMB22A1 63.4 159

NMB991 15 38.4

NMB100 32.8 3,095.4

NMB-INJ-01 6.8 583.9

NMB-INJ-02 7.8 595.9

NMB-INJ-03 8 589.2

W1032 95.4 5,879.2

Note:

1 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and

NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

Documentation of all treatment and sampling activities will continue to be provided in the monthly and

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NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 746

Month: June 2024

Reporting Period: 6/1/2024 – 6/30/2024

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained

The weekly inspections were completed on 6/6/24, 6/12/24, 6/20/24, and 6/26/24.

The second quarter 2024 sampling event was conducted on 6/18/24 (below are the results and attached is a location map). Samples were collected from two extraction wells (W101, W102) and three monitoring wells (NMB45B, NMB46B, NMB62A). Per the USEPA approved optimization changes to the performance monitoring, wells NMB22A and NMB99 will be excluded from the quarterly sampling quarterly sampling event is scheduled for September 2024.

Northern Boundary (Q2 2024 Groundwater Results)

MCL

(µg/L)

W101 W102 NMB45B NMB46B NMB62A

cis-1,2-Dichloroethene 70 0.94 J 2.5 1.5 J 5.7 BQL

Tetrachloroethene 5 BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL

Trichloroethene 5 0.69 J 2.5 1 4.2 BQL

Vinyl chloride 2 BQL BQL BQL BQL BQL

Note:

BQL = below quantitation limit

Report No. 746

Sodium percarbonate socks were deployed three times in treatment wells: NMB22A, NMB99, NMB100, continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

Below are the total amounts of sodium percarbonate introduced to the treatment wells during June and from 12/2/16 through 6/30/24.

Introduced (pounds)

June 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-6/30/24

NMB22A1 45.6 204.6

NMB991 10.8 49.2

NMB100 25.4 3,120.8

NMB-INJ-01 5.6 589.5

NMB-INJ-02 6.4 602.3

NMB-INJ-03 5.4 594.6

W1032 72 5,951.2

Note:

1 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and

NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

Documentation of all treatment and sampling activities will continue to be provided in the monthly and

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A

@A

NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 747

Month: July 2024

Reporting Period: 7/1/2024 – 7/31/2024

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained

The weekly inspections were completed on 7/3/24, 7/11/24, 7/18/24, and 7/24/24.

Below are the sampling results from the second quarter 2024 and attached is a location map. The next

MCL

(µg/L)

W101 W102 NMB45B NMB46B NMB62A

cis-1,2-Dichloroethene 70 0.94 J 2.5 1.5 J 5.7 BQL

Tetrachloroethene 5 BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL

Trichloroethene 5 0.69 J 2.5 1 4.2 BQL

Vinyl chloride 2 BQL BQL BQL BQL BQL

Note:

BQL = below quantitation limit

Sodium percarbonate socks were deployed five times in treatment wells: NMB22A, NMB99, NMB100, continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

Below are the total amounts of sodium percarbonate introduced to the treatment wells during July and from 12/2/16 through 7/31/24.

Report No. 747

Introduced (pounds)

July 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-7/31/24

NMB22A1 79 283.6

NMB991 19 68.2

NMB100 41 3,161.8

NMB-INJ-01 9.8 599.3

NMB-INJ-02 10.2 612.5

NMB-INJ-03 9 603.6

W1032 118 6,069.2

Note:

1 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and

NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

Documentation of all treatment and sampling activities will continue to be provided in the monthly and

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A

@A

NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 748

Month: August 2024

Reporting Period: 8/1/2024 – 8/31/2024

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained

The weekly inspections were completed on 8/1/24, 8/7/24, 8/13/24, 8/21/24, and 8/27/24.

Below are the sampling results from the second quarter 2024 and attached is a location map. The next

MCL

(µg/L)

W101 W102 NMB45B NMB46B NMB62A

cis-1,2-Dichloroethene 70 0.94 J 2.5 1.5 J 5.7 BQL

Tetrachloroethene 5 BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL

Trichloroethene 5 0.69 J 2.5 1 4.2 BQL

Vinyl chloride 2 BQL BQL BQL BQL BQL

Note:

BQL = below quantitation limit continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

Below are the total amounts of sodium percarbonate introduced to the treatment wells during August and from 12/2/16 through 8/31/24.

Report No. 748

Introduced (pounds)

August 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-8/31/24

NMB22A1 65.8 349.4

NMB991 16.8 85

NMB100 33 3,194.8

NMB-INJ-01 8.2 607.5

NMB-INJ-02 8.6 621.1

NMB-INJ-03 9 612.6

W1032 102 6,171.2

Note:

1 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and

NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

Documentation of all treatment and sampling activities will continue to be provided in the monthly and

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A

@A

NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 749

Month: September 2024

Reporting Period: 9/1/2024 – 9/30/2024

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained

The weekly inspections were completed on 9/3/24, 9/10/24, 9/17/24, and 9/23/24.

The third quarter 2024 sampling event was conducted on 9/10/24 (below are the results and attached is a location map). Samples were collected from two extraction wells (W101, W102) and three monitoring wells (NMB45B, NMB46B, NMB62A). Per the USEPA approved optimization changes to the performance monitoring, wells NMB22A and NMB99 will be excluded from the quarterly sampling quarterly sampling event is scheduled for December 2024.

Northern Boundary (Q3 2024 Groundwater Results)

MCL

(µg/L)

W101 W102 NMB45B NMB46B NMB62A

cis-1,2-Dichloroethene 70 1.2 J 2.5 1.7 J 5.6 BQL

Tetrachloroethene 5 BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL

Trichloroethene 5 0.9 J 2.6 1.2 4.2 BQL

Vinyl chloride 2 BQL BQL BQL BQL BQL

Note:

BQL = below quantitation limit

Report No. 749 continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

Below are the total amounts of sodium percarbonate introduced to the treatment wells during September and from 12/2/16 through 9/30/24.

Introduced (pounds)

September 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-9/30/24

NMB22A1 66.9 416.3

NMB991 17.2 102.2

NMB100 34.2 3,229

NMB-INJ-01 8.8 616.3

NMB-INJ-02 9 630.1

NMB-INJ-03 9 621.6

W1032 97.6 6,268.8

Note:

1 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and

NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

Documentation of all treatment and sampling activities will continue to be provided in the monthly and

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A

@A

NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 750

Month: October 2024

Reporting Period: 10/1/2024 – 10/31/2024

Explanation of Significant Differences (ESD). In an effort to be prepared, the system will be maintained

The weekly inspections were completed on 10/1/24, 10/9/24, 10/15/24, 10/22/24, and 10/28/24.

Below are the sampling results from the third quarter 2024 and attached is a location map. The next quarterly sampling event is scheduled for December 2024.

Northern Boundary (Q3 2024 Groundwater Results)

MCL

(µg/L)

W101 W102 NMB45B NMB46B NMB62A

cis-1,2-Dichloroethene 70 1.2 J 2.5 1.7 J 5.6 BQL

Tetrachloroethene 5 BQL BQL BQL BQL BQL trans-1,2-Dichloroethene 100 BQL BQL BQL BQL BQL

Trichloroethene 5 0.9 J 2.6 1.2 4.2 BQL

Vinyl chloride 2 BQL BQL BQL BQL BQL

Note:

BQL = below quantitation limit

Sodium percarbonate socks were deployed five times in treatment wells: NMB22A, NMB99, NMB100, continue to help reduce the residual TCE concentrations that have been above the MCL (5 µg/L) in wells

Below are the total amounts of sodium percarbonate introduced to the treatment wells during October and from 12/2/16 through 10/31/24.

Report No. 750

Introduced (pounds)

October 2024

Total Sodium Percarbonate

Introduced (pounds)

12/2/16-10/31/24

NMB22A1 80.2 496.5

NMB991 18.6 120.8

NMB100 26.2 3,255.2

NMB-INJ-01 10.8 627.1

NMB-INJ-02 11.4 641.5

NMB-INJ-03 10.6 632.2

W1032 120.6 6,389.4

Note:

1 = Socks were deployed in wells NMB22A and NMB99 starting on 03/18/24. NMB22A and

NMB99 will be treated for a period of one calendar year and not be sampled during treatment.

Documentation of all treatment and sampling activities will continue to be provided in the monthly and

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A

@A

NMB-INJ-01

NMB100

NMB-INJ-03

NMB-INJ-02

Southeast Area

Former Missile Maintenance Area

(see Inset Map)

Northern Boundary Area

W101

W103

NMB03A

NMB61A

NMB53A

NMB55A

W102

W108

W107

W106

W105 W104

NMB07B(R)

NMB52B

NMB99

NMB45B

NMB22A

NMB62A

NMB46B

NMB36A

NMB32A

NMB96B

NMB97B

Legend

$# Injection Well

@A Monitoring Well

&( Extraction Well

Installation Boundary

Buildings

Streams

Paving

Wetland o Coordinate Projection:

UTM Zone 18 (feet), NAD 83

Former Nike Missile Site Aberdeen Proving Ground

Maryland

Key Map

Map Area

0 200 400100

Feet

General groundwater flow direction

@A

$#$#$#NMB-INJ-01

NMB-INJ-02

NMB-INJ-03

W1

NMB07B(R)

General groundwater flow direction

Former Missile Maintenance Area

Report No. 751

FORMER NIKE MISSILE BATTERY

GROUNDWATER TREATMENT FACILITY

MONTHLY STATUS REPORT

Month: November 2024

Reporting Period: 11/1/2024 – 11/30/2024

System…