WA-01171_10171_CA_RPTS_20220928

3502 Hayes Road • Monroe, North Carolina 28110
113 West Firetower Road, Suite G • Winterville, North Carolina 28590
Phone [phone] • [phone] • Fax [phone]
Engineering Certification: C-2727 • Geology Certification: C-127
September 28, 2022

Ms. Carrie Stone
North Carolina Department of
Environmental Quality
Washington Regional Office
943 Washington Square Mall
Washington, North Carolina 27889

Re: Plume Stability Analysis
Tee Lok Corporation
818 Soundside Road
Edenton, North Carolina
Chowan County
Incident Number: 10171
GRI Project Number: 2298

Dear Ms. Stone;

Geological Resources, Inc. (GRI) presents the results of the plume stability analysis for the Tee Lok
Corporation site in Edenton, North Carolina. The activities were conducted in order to evaluate if the risk
classification for the site can be lowered.

On September 19, 2022, a GSI Mann-Kendall Toolkit for Plume Stability Analysis (Mann-Kendall) was
prepared for the site. Based on the results of the Mann-Kendall analysis, the contaminant plume at the
site is generally stable. Telephone conversations between the GRI project manager and the NCDEQ
incident manager completed on September 26 and 28, 2022, discussed the results of the Mann-Kendall
analysis. Additionally, Former WSW-1 that had been located within 1,000 feet of the site was
determined to not be a potable water supply well. A Site Location Map, Site Map and Receptor Survey
Map have been included as Figures 1, 2, and 3. Past ground water sampling results, as well as well
construction information and the Mann-Kendall analysis are attached.

Please contact me at 704-698-1253 or [e-mail] with any questions or
comments.

Tee Lok Corporation
September 2022 Plume Stability Analysis
Page 2 of 3

3502 Hayes Road • Monroe, North Carolina 28110
Phone [phone] • [phone] • Fax [phone]

Sincerely,

William Regenthal, P. G.
Project Manager
SITE
7 8 1 3 0 0 9 6 5 1 6 0
781300924506781300965160 782313036069
782300057485
7823002434387 8 2 3 0 0 0 4 6 7 6 3
7 8 2 3 1 7 0 2 5 2 4 2
782313034667
781300935169 782300248419782313130622781300946260
7823142352047
8
2
3
0
0
1
5
7
5
8
5
782300341388782300351621
782313129504
782313137525
7
82
3
0
0
1
42
3
5
6
782313128766
782313137257782300146333
782313138010781300939605
782318227443
782313044118
78231423520478231712147678231423879878231
32327347823000491967
8
2
3
0
0
0
4
7
3
9
4
782314331542782313134842
78
2
3
1
7
1
2
6
2
0
8782313136854 782313139874
78231822622078231712
41217
8
2
3
1
4
3
3
2
8
6
0782300341105
782314235682
782317122214 782317220156782317128393782317221255782318321267782300141136782314238568
782300149453
782314236831782300149163
782300149257
782318 3 2 2 4 1 57823142358027823143323 1 3782300245114
782314330051782300149546
782313138824782314331220782317127340782317222148782317223149782317224139782317129155782314320844
782314321681
782314323938
782314321711
782317222346
782317128164
782317224318
782317028140
782317223327
782318225317
782314333160
782317029058 782317127161782317120066
782300049576
782317126077782317121074
782317125083
782318312963782318310936
782318324343
782314334204
782300345521
782314335557
782318217963
SOUNDSIDE
ATHOLMIDWAYASHLEYSAILOR
BAYVIEWAIRPORTBIO-COMPATLANTIC FORESTROSE TRAILER PARKWSW-1
FIGURE 3: RECEPTOR SURVEY MAPTEE LOK CORPORATION818 SOUNDSIDE ROADEDENTON, CHOWAN COUNTYNORTH CAROLINAINCIDENT NO. 10171
PREPARED BY:GEOLOGICAL RESOURCES, INC.MAY 29, 2007
0 300150
Feet1 inch equals 300 feet
Legend
I-1 Light Industrial District Zoning
R-25 Residential District Zoning
RMH-25 Residential District Zoning
B-1 General Business District Zoning
Water Supply Well
1,500-FOOT RADIUS
MW-1 11/10/05 05/17/93 100.00 NM ---12.5 2.5-12.5
11/10/05 4.54 95.15
10/26/06 5.28 94.41
01/17/07 3.93 95.76
04/17/07 3.33 96.36
07/13/07 5.24 94.45
02/19/08 5.45 94.24
02/09/09 5.03 94.66
MW-3 11/10/05 10/06/93 99.62 NM ---12.5 2.5-12.5
10/26/06 4.99 94.97
01/17/07 3.78 96.18
04/17/07 3.51 96.45
07/13/07 5.04 94.92
02/19/08 4.04 95.92
02/09/09 4.49 95.47
MW-4 11/10/05 10/12/93 99.96 NM ---25 20-25
11/10/05 4.03 95.49
10/26/06 NM ---
01/17/07 3.19 96.33
04/17/07 3.26 96.26
07/13/07 3.37 96.15
02/19/08 4.75 94.77
02/09/09 3.51 96.01
11/10/05 4.77 95.22
10/26/06 5.34 94.65
01/17/07 4.32 95.67
04/17/07 3.50 96.49
07/13/07 5.24 94.75
02/19/08 5.79 94.20
02/09/09 5.39 94.60
MW-7 11/10/05 10/27/93 100.18 NM ---13 3-13
11/10/05 3.29 96.33
10/26/06 4.48 95.14
01/17/07 3.40 96.22
04/17/07 3.20 96.42
07/13/07 4.59 95.03
02/19/08 3.60 96.02
02/09/09 99.45 4.11 95.34
10/26/06 6.14 94.42
01/17/07 5.08 95.48
04/17/07 4.41 96.15
07/13/07 5.82 94.74
02/19/08 6.45 94.11
02/09/09 6.18 94.38
10/26/06 5.51 94.55
01/17/07 4.35 95.71
04/17/07 3.78 96.28
07/13/07 5.18 94.88
02/19/08 5.85 94.21
02/09/09 5.57 94.49
10/26/06 5.72 94.32
01/17/07 4.52 95.52
04/17/07 3.71 96.33
07/13/07 5.85 94.19
02/19/08 6.03 94.01
02/09/09 5.75 94.29
10/26/06 3.80 95.88
01/17/07 2.77 96.91
04/17/07 2.25 97.43
07/13/07 3.51 96.17
02/19/08 2.66 97.02
02/09/09 3.75 95.93
MW-2
Screened
IntervalWell No.Date
Gauged
Date
Completed
Top of
Casing
Elevation
Ground
Water
Elevation
Depth to
Ground
Water
99.6910/05/93
APPENDIX C
SUMMARY OF HISTORICAL GROUND WATER ELEVATION DATA
TEE LOK CORPORATION
Well
Depth
2.5-12.512.5
2-121299.9607/11/06MW-3R
MW-5
2.5-12.512.599.9910/12/93MW-6
4-9999.5210/07/93
13 3-13MW-8
2-1212
09/20/95 99.62
100.5607/11/06MW-9
MW-11 2-1212100.0407/11/06
07/12/06
1-1111100.0607/11/06MW-10
2-7799.68MW-12
Page 1 of 2
Screened
IntervalWell No.Date
Gauged
Date
Completed
Top of
Casing
Elevation
Ground
Water
Elevation
Depth to
Ground
Water
APPENDIX C
SUMMARY OF HISTORICAL GROUND WATER ELEVATION DATA
TEE LOK CORPORATION
Well
Depth
10/26/06 3.71 95.99
01/17/07 2.04 97.66
04/17/07 1.60 98.10
07/13/07 2.50 97.20
02/19/08 1.65 98.05
02/09/09 3.67 96.03
MW-14 02/09/09 02/09/09 99.92 4.78 95.14 12.5 2.5-12.5
10/26/06 6.96 93.34
01/17/07 5.32 94.98
04/17/07 5.19 95.11
07/13/07 7.28 93.02
02/19/08 7.96 92.34
02/09/09 7.06 93.24
Notes:
reported in feet.
08/24/06 100.30 37 32-37
07/12/06 799.70
• NM: Not Measured; well has been covered, destroyed or could not be located.
• Elevations relative to a temporary benchmark with an assumed elevation of 100.00 feet; data
• No well construction records were available for MW-1 through MW-8; well construction
information is based on field measurements and field notes and assumes standard industry practices.
TW-1
2-7MW-13
Page 2 of 2
Well
No.Date Benzene Toluene Ethylbenzene Xylenes MTBE IPE Naphthalene
1 1,000 550 530 200 70 21
08/22/95 91 240 87 220 110 NR NR
11/09/95 <1.0 <1.0 1.3 <1.0 <5.0 NR NR
02/13/96 <1.0 <1.0 <1.0 1.9 <1.0 NR NR
05/20/96 <1.0 <1.0 <1.0 <1.0 <1.0 NR NR
11/10/05 NS NS NS NS NS NS NS
08/22/95 <1.0 <1.0 <1.0 <1.0 <5.0 NR NR
11/09/95 <1.0 <1.0 <1.0 <1.0 <5.0 NR NR
02/13/96 <1.0 <1.0 <1.0 <1.0 2.7 NR NR
05/20/96 <1.0 <1.0 <1.0 <1.0 <1.0 NR NR
11/10/05 <1.0 <5.0 <1.0 <3.0 1.6 <1.0 <5.0
10/26/06 <1.0 <5.0 <1.0 <3.0 2.0 <1.0 <5.0
01/17/07 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 1.03 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 1.1 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 <1.0 <5.0 <1.0
02/09/09 0.89 <0.70 1.7 J 2.5 J <0.50 <1.0 1.6 JB
08/22/95 <1.0 <1.0 <1.0 <1.0 <5.0 NR NR
11/09/95 <1.0 <1.0 <1.0 <1.0 <5.0 NR NR
02/13/96 <1.0 <1.0 <1.0 <1.0 <1.0 NR NR
05/20/96 <1.0 <1.0 <1.0 <1.0 <1.0 NR NR
11/10/05 NS NS NS NS NS NS NS
10/26/06 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
01/17/07 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 <1.0 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 <1.0 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 2.01 <5.0 <1.0
02/09/09 <0.60 <0.70 <0.50 <1.0 <0.50 <1.0 <0.60
08/22/95 1.7 3.7 <1.0 3.8 96 NR NR
11/09/95 4 <1.0 <1.0 <1.0 <5.0 NR NR
02/13/96 4.9 <1.0 <1.0 <1.0 280 NR NR
05/20/96 <1.0 <1.0 <1.0 <1.0 <1.0 NR NR
11/10/05 NS NS NS NS NS NS NS
08/22/95 <1.0 <1.0 <1.0 <1.0 57 NR NR
11/09/95 <1.0 <1.0 <1.0 <1.0 <5.0 NR NR
02/13/96 <1.0 <1.0 <1.0 <1.0 150 NR NR
05/20/96 540 <1.0 240 460 1,800 NR NR
11/10/05 <1.0 <5.0 <1.0 <3.0 1.3 <1.0 <5.0
10/26/06 NS NS NS NS NS NS NS
01/17/07 <1.0 <5.0 <1.0 <3.0 1.2 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 1.67 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 <1.0 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 <1.0 <5.0 <1.0
02/09/09 <0.60 <0.70 <0.50 <1.0 <0.50 <1.0 0.62 JB
08/22/95 NS NS NS NS NS NS NS
11/09/95 NS NS NS NS NS NS NS
02/13/96 NS NS NS NS NS NS NS
05/20/96 3.2 <1.0 <1.0 <1.0 17 NR NR
11/10/05 160 <50 54 39 330 <1.0 81
10/26/06 70 <5.0 28 3.6 140 <1.0 13
01/17/07 310 21 410 470 320 1.0 110
04/17/07 136 <1.0 55.4 37.2 185 <1.0 38.6
07/13/07 67 <5.0 52 16 110 <5.0 45
02/19/08 67.2 1.41 99.9 71.5 173 <5.0 27.2
02/09/09 81 7.0 160 250 220 <1.0 33 B
08/22/95 <1.0 1 <1.0 <1.0 <5.0 NR NR
11/09/95 <1.0 <1.0 <1.0 <1.0 <5.0 NR NR
02/13/96 <1.0 <1.0 <1.0 <1.0 <1.0 NR NR
05/20/96 11 15 12 <1.0 160 NR NR
11/10/05 NS NS NS NS NS NS NS
MW-3R
MW-2
APPENDIX D
SUMMARY OF HISTORICAL LABORATORY ANALYTICAL RESULTS
GROUND WATER SAMPLES
TEE LOK CORPORATION
MAC
MW-3
MW-1
MW-4
MW-7
MW-6
MW-5
Page 1 of 2
Well
No.Date Benzene Toluene Ethylbenzene Xylenes MTBE IPE Naphthalene
1 1,000 550 530 200 70 21
APPENDIX D
SUMMARY OF HISTORICAL LABORATORY ANALYTICAL RESULTS
GROUND WATER SAMPLES
TEE LOK CORPORATION
MAC
08/22/95 NS NS NS NS NS NR NR
11/09/95 NS NS NS NS NS NR NR
02/13/96 160 1,000 76 440 1,600 NR NR
05/20/96 430 170 290 300 1,700 NR NR
11/10/05 <1.0 <5.0 29 73 <1.0 <1.0 15
10/26/06 2.4 5.1 100 300 5.2 <1.0 49
01/17/07 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
04/17/07 <1.0 <1.0 3.72 <3.0 <1.0 <1.0 <5.0
07/13/07 <25 230 670 2,000 <25 <25 120
02/19/08 3.25 24.5 135 391 3.53 <5.0 29.3
02/09/09 <0.60 <0.70 28 34 <0.50 <1.0 10 B
10/26/06 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
01/17/07 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 <1.0 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 <1.0 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 <1.0 <5.0 <1.0
02/09/09 <0.60 <0.70 <0.50 <1.0 <0.50 <1.0 <0.60
10/26/06 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
01/17/07 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 1.12 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 <1.0 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 <1.0 <5.0 <1.0
02/09/09 <0.60 <0.70 <0.50 <1.0 <0.50 <1.0 <0.60
10/26/06 <1.0 <5.0 <1.0 <3.0 3.8 <1.0 <5.0
01/17/07 <1.0 <5.0 <1.0 <3.0 3.1 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 <1.0 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 <1.0 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 2.00 <5.0 <1.0
02/09/09 <0.60 <0.70 <0.50 <1.0 <0.50 <1.0 <0.60
10/26/06 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
01/17/07 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 <1.0 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 <1.0 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 <1.0 <5.0 <1.0
02/09/09 <0.60 <0.70 <0.50 <1.0 <0.50 <1.0 <0.60
10/26/06 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
01/17/07 55 <5.0 7.2 27 2.7 <1.0 <5.0
02/05/07 <1.0 <5.0 <1.0 <3.0 <1.0 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 <1.0 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 <1.0 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 <1.0 <5.0 <1.0
02/09/09 <0.60 <0.70 <0.50 <1.0 <0.50 <1.0 <0.60
MW-14 02/09/09 <0.60 <0.70 <0.50 <1.0 <0.50 <1.0 <0.60
10/26/06 <1.0 <5.0 <1.0 <3.0 18 <1.0 <5.0
01/17/07 <1.0 <5.0 <1.0 <3.0 11 <1.0 <5.0
04/17/07 <1.0 <1.0 <1.0 <3.0 15.1 <1.0 <5.0
07/13/07 <1.0 <1.0 <1.0 <2.0 11 <1.0 <2.0
02/19/08 <1.0 <1.0 <1.0 <3.0 39.4 <5.0 <1.0
02/09/09 <0.60 <0.70 <0.50 <1.0 18 <1.0 <0.60
Notes:
• Detectable concentrations of 1,3,5-trimethylbenzene and/or 1,2,4-trimethylbenzene that did not exceed the MACs were reported in
the ground water samples collected from MW-2, MW-5, MW-6 and MW-8 on February 9, 2009.
• NS: Not sampled; well was either covered or destroyed.
• MAC: Maximum allowable concentration specified in T15A NCAC 2L.0202.
• Analysis for volatile organics by EPA Method 602 or 6210D; results reported in µg/l.
• Concentrations in bold face type exceeded the MAC.
• NR: Analysis not requested.
TW-1
MW-8
MW-12
MW-11
• <: Less than the report limit specified in the laboratory report.
MW-13
MW-10
MW-9
Page 2 of 2
Evaluation Date:Job ID:
Facility Name:Constituent:
Conducted By:Concentration Units:μg/L
Sampling Point ID:MW-6 - Benz MW-6 - MTBE MW-6 Naph
Sampling Sampling
Event Date
1 20-May-96 3.2 17
2 10-Nov-05 160 330 81
3 26-Oct-06 70 140 13
4 17-Jan-07 310 320 110
5 17-Apr-07 136 185 38.6
6 13-Jul-07 67 110 45
7 19-Feb-08 67.2 173 27.2
8 9-Feb-09 81 220 33
9
10
11
12
13
14
15
16
17
18
19
20
Coefficient of Variation:0.83 0.56 0.68
Mann-Kendall Statistic (S):0 2 -5
Confidence Factor:45.2%54.8%71.9%
Concentration Trend:Stable No Trend Stable
Notes:
1.At least four independent sampling events per well are required for calculating the trend. Methodology is valid for 4 to 40 samples.
2.Confidence in Trend = Confidence (in percent) that constituent concentration is increasing (S>0) or decreasing (S<0): >95% = Increasing or Decreasing;
≥ 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, S≤0, and COV ≥ 1 = No Trend; < 90% and COV < 1 = Stable.
3.Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41(3):355-367, 2003.
DISCLAIMER: The GSI Mann-Kendall Toolkit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, correctness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
GSI Environmental Inc., www.gsi-net.com
BENZENE/MTBE/NAPHTHALENE CONCENTRATION (μg/L)
19-Sep-22
Tee Lok Benzene/MTBE/Naphthalene
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
William Regenthal
10171
1
10
100
1000
01/93 10/95 07/98 04/01 01/04 10/06 07/09 04/12Concentration (μg/L)Sampling Date
MW-6 - Benz
MW-6 - MTBE
MW-6 Naph