Mayo Background GW Tech Memo Dec 2016_20171005

TECHNICAL MEMORANDUM
Date: December 15, 2016 File: 1026.105.19
To: Kimberlee Witt (Duke Energy)
Cc: Kathy Webb ( Terra)
From: Jerry Wylie
Subject: Quantification Valid Background Groundwater Samples for Statistics
Calculations - Mayo Steam Electric Plant
Proposed Preliminary Background Threshold Values (PPBTVs) for groundwater will be
calculated for CAMA assessment constituents identified with concentrations greater than the 2L
or IMAC at the Mayo Steam Electric Plant (Site). A summary of background well analytical
results was originally presented in the Mayo Corrective Action Plan, Part 1 submitted
December 2015 and updated in the CSA Supplement 1 submitted July 2016. Table 1 provides a
summary of existing background well data for each flow zone and indicates which samples are
considered for use in statistical calculations to determine concentrations of naturally occurring
(background) inorganic constituents in groundwater. Well locations are presented on Figure 1.
Additional sampling has been conducted since September 2016 that can be used to augment the
dataset provided herein once the data are available. The following discussion quantifies the
number of valid results to date within each flow zone at the Site and provides justification for
including monitoring well MW-11BR in the evaluation of PPBTVs at the Site.
BACKGROUND WELL DATA ANALYSIS
The current background monitoring well network consists of wells installed within three flow
zones (surficial, transition zone, and bedrock). Samples from these wells must meet the
following criteria to be considered valid for determining PPBTVs:
y Sample pH is less than or equal to (<) 8.5 standard units (S.U.);
47 Sample turbidity is less than or equal to (<) 10.0 Nephelometric Turbidity Units (NTUs);
and
0 Result is not a statistical outlier identified for background sample data collected through
April 2016 (SynTerra, July 7, 2016; CSA Supplement 1).
Professional judgement can be used to retain data that does not meet these criteria (such as pH);
however, the decision to retain data that does not satisfy these criteria must be documented.
For Mayo, only an evaluation with pH <8.5 was conducted because there were no measured pH
values between 8.5 and 9.0.Only one proposed background well (MW-11BR) included a pH
value greater than 8.5 (discussed below).
P: \ Duke Energy Progress.1026 \ 105. Mayo Ash Basin GW Assessment Plan \ 19.EG_CSASUP \ Statistics \ Background
GW NovDec 2016\MAYO BG Analytical GW FINAL Dec 2016.docx

Quantification of Valid Background Groundwater Samples December 15, 2016
Mayo Steam Electric Plant
SURFICIAL
Page 2 of 2
One background well (MW-12S) is screened within the surficial flow zone. Six valid sampling
events, for most analytes, have occurred since June 2015. One sample (June 18, 2015) has been
eliminated due to a turbidity value in excess of 10 NTU. As previously mentioned, an event was
conducted in early November 2016 which will provide a seventh sampling event for most
analytes. In addition, an eighth event was completed during the first week of December 2016.
With the exception of a radium and uranium, the surficial background data set will satisfy the
requirements for the minimum number of samples to conduct statistical analysis by the end of
2016. For radium and uranium, eight valid sample results are expected to be complete by April
2017 (seventh event in February 2017 and eighth event in April 2017).
TRANSITION ZONE
Two background wells (BG-02 and MW-12D) are screened within the transition zone. A
minimum of eight valid sample events have occurred for transition zone wells (since December
2010 for BG-02 and since June 2015 for MW-12D). With the exception of radium and uranium,
the transition zone background data set will satisfy the requirements for the minimum number
of samples to conduct statistical analysis by the end of 2016. For radium and uranium, eight
valid sample results are expected to be complete by February 2017.
BEDROCK
Five wells (BG-01, MW-10BR, MW-11BR, MW-13BR, and MW-14BR) are screened in the
bedrock flow zone. The bedrock background data set will satisfy the requirements for the
minimum number of samples to conduct statistical analysis by the end of 2016. Groundwater
samples eliminated from the background dataset include elevated or not measured turbidity in
eight samples from BG-01, one sample from MW-10BR, and one sample from MW-14BR.
The data from proposed background bedrock monitoring well MW-11BR has been retained and
included with the dataset for statistical analysis although the measured pH values exceed 8.5
and 9.0 for six of the seven monitoring events. Monitoring well MW-11BR was installed within
a basic/ultrabasic bedrock type tentatively identified as a meta -igneous rock (meta-gabbro).
Naturally occurring high pH groundwater has, in some studies, been linked to the presence of
ultrabasic rocks. Additional evaluation and testing of rock core from MW-11BR is underway to
validate this hypothesis and determine whether the values noted from MW-11BR may be
attributed to natural conditions or some other explanation. For now, the data from MW-11BR
has been retained for statistical evaluation. If the additional evaluation finds that the natural
conditions are not the source of the elevated pH, the data will not be used to calculate PPBTVs.
ATTACHMENTS
Table 1: Background Groundwater Data Summary through September 2016
Figure 1: Well Location Map
P: \ Duke Energy Progress.1026 \ 105. Mayo Ash Basin GW Assessment Plan \ 19.EG_CSASUP \ Statistics \ Background
GW NovDec 2016\MAYO BG Analytical GW FINAL Dec 2016.docx

TABLE 1
BACKGROUND GROUNDWATER DATA SUMMARY THROUGH 2O16-09
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
ph
Water
Level
Temp
Spec
Coed
DO
ORP
Eh
Turbidity
Antimony
Arsenic
Barium
Boron
Chromium
(V1)
Chromium
Cobalt
Iron
Lead
Manganese
Sodium
Strontium
Thallium
Total
Dissolved
Solids
Vanadium
Radium-226
Radium-228
Uranium-233
Uranium-234
Uranium-236
Uranium-238
Reporting Units
S.U.
ft
Deg C
umhos/cm
mg/L
I mV
mV
NTUs
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
mg/L
ug/L
ug/L
mg/L
ug/L
pCi/L
pCi/L
ug/mL
ug/mL
ug/mL
ug/mL
15A NCAC 02L Standard
6.5-8.5
NE
NE
NE
NE
NE
NE
NE
1*
10
700
700
0.07^
10
1*
300
15
50
NE
NE
0.2*
500
0.3*
NE
NE
NE
NE
NE
NE
Sample ID
Sample
Collection Date
Field Parameters
Analytical Results
Saprolite
MW-12S
0611812015
5.7
30.61
21
55
3.66
127
332
10.6
<1
<I
24
<50
NA
1.61
1.09
295
<I
26
6.79
27
<0.2
50
0.403
NA
NA
NA
NA
NA
NA
MW-12S
06/24/2015
6.0
30.75
22
53
2.92
31
236
3.4
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.84
<3
<0.00005
<0.00005
<0.00005
<0.0002
MW-12S
09/10/2015
5.8
31.69
20
47
2.3
34
239
6.31
<1
<1
19
<50
NA
3.23
1.02
108
<1
253
5.43
23
<0.2
55
<0.3
NA
NA
NA
NA
NA
NA
MW-12S
12/02/2015
5.7
32.15
17
68
2.7
159
364
6.9
<1
<1
16
<50
0.043
7.17
<1
336
<1
152
5.08
21
<0.2
26
0.313
NA
NA
NA
NA
NA
NA
MW-12S
01/07/2016
5.8
31.69
10
111
2.86
185
390
9.89
<1
<1
11
<50
0.038
1.43
<1
178
<1
68
4.76
18
<0.2
35
<0.3
NA
NA
NA
NA
NA
NA
MW-12S
04/06/2016
5.8
29.91
14
46
2.91
159
364
7.42
<1
<1
12
<50
0.058
<1
<1
338
<1
24
5.49
17
<0.2
29
0.408
0.537
<3
<0.00005
<0.00005
<0.00005
0.000217
MW-125
07/11/2016
4.9
28.87
19
54
0.43
92
297
9.12
<1
<1
13
<50
0.045
<1
<1
385
<1
34
4.34
21
<0.2
43
0.974
<1
<1
<0.00005
<0.00005
<0.00005
<0.0002
MW-125
09/07/2016
5.8
29.93
20
42
It
141
346
9.24
<1
<1
12
<50
0..
<1
<1
270
<1
11
4.78
16
<0.2
52
0.711
1.56
<1
<0.00005
<0.00005
<0.00005
<0.0002
Total Count of Valid Samples
7
7
6
6
6
5
6
4
9 jr
1 4
4
Transition Zone
BG-02
1210212010
6.6
35.57
19
576
NM
NM
NM
13
<0.5
<5
81.8
<50
NA
6.7
NA
2660
<5
198
NA
NA
<0.1
349
NA
NA
NA
NA
NA
NA
NA
BG-02
0412012011
6.3
33.35
21
623
1.26
7
212
12.1
<0.5
<5
61.3
<50
NA
<5
NA
439
<5
71.4
NA
NA
<0.1
382
NA
NA
NA
NA
NA
NA
NA
BG-02
07/11/2011
6.3
35.45
26
706
0.32
-77
128
9.2
<0.5
<5
64.8 B
<50
NA
10.2
NA
559
<5
64.2
NA
NA
<0.1
367 B
NA
NA
NA
NA
NA
NA
NA
BG-02
11/03/2011
6.3
35.90
17
671
0.67
-98
107
5.63
<0.5
<5
67.7
<50
NA
7.5
NA
312
<5
36.7
NA
NA
<0.1
341
NA
NA
NA
NA
NA
NA
NA
BG-02
04/04/2012
6.3
35.71
21
647
0.34
-93
113
5.55
<0.5
<5
61.5
<50
NA
<5
NA
152
<5
27
NA
NA
<0.1
412
NA
NA
NA
NA
NA
NA
NA
BG-02
07/09/2012
6.3
35.94
20
652
0.51
-78
127
9.47
<0.5
<5
53.4
<50
NA
5.9
NA
460
<5
54.9
NA
NA
<0.1
382
NA
NA
NA
NA
NA
NA
NA
BG-02
11/05/2012
6.3
36.20
17
640
0.51
90
295
9.02
<0.5
<5
60.2
<50
NA
6
NA
759
<5
43.7
NA
NA
<0.1
389
NA
NA
NA
NA
NA
NA
NA
BG-02
04/10/2013
6.3
35.33
18
725
0.17
-17
188
8.5
<1
<1
66
<50
NA
<5
NA
646
<1
111
NA
NA
<0.2
430
NA
NA
NA
NA
NA
NA
NA
BG-02
07/09/2013
6.4
34.66
19
695
0.31
-120
85
8.08
<1
<1
69
<50
NA
<5
NA
1130
<1
248
NA
NA
<0.2
430
NA
NA
NA
NA
NA
NA
NA
BG-02
11/13/2013
6.4
34.40
17
658
0.1
18
223
9.5
<1
<1
62
<50
NA
<5
NA
841
<1
177
NA
NA
<0.2
360
NA
NA
NA
NA
NA
NA
NA
BG-02
04/01/2014
6.4
33.78
17
709
0.2
68
273
7.5
<1
<1
71
<50
NA
<5
NA
943
<1
226
NA
NA
<0.2
450
NA
NA
NA
NA
NA
NA
NA
BG-02
07/18/2014
6.4
33.20
18
664
0.14
2
207
7.71
<1
<1
65
<50
NA
<5
NA
1010
<1
244
NA
NA
<0.2
400
NA
NA
NA
NA
NA
NA
NA
BG-02
11/12/2014
6.3
33.02
18
630
0.12
21
226
5.33
<1
<1
61
<50
NA
<5
NA
647
<1
180
NA
NA
<0.2
370
NA
NA
NA
NA
NA
NA
NA
BG-02
04/13/2015
6.3
31.93
18
652
0.2
-11
194
7.09
<1
<1
54
<50
NA
<5
<1
435
<1
150
49.7
NA
<0.2
380
NA
NA
NA
NA
NA
NA
NA
BG-02
07/07/2015
6.5
31.53
19
623
0.3
-129
76
8.51
<1
<1
54
<50
NA
<5
<1
467
<1
135
48.2
NA
<0.2
370
5.88
NA
NA
NA
NA
NA
NA
BG-02
09/11/2015
6.4
31.49
18
537
0.03
-40
165
6.86
<1
<1
50
<50
NA
4.05
<1
244
<1
130
44.6
291
<0.2
330
4
NA
NA
NA
NA
NA
NA
BG-02
1110312015
6.7
31.89
18
14
7.88
59
264
11.3
<I
<I
51
<50
NA
<5
<I
513
<I
102
46.7
318
<0.2
350
6.63
NA
NA
NA
NA
NA
NA
BG-02
12/09/2015
6.4
31.66
16
612
0.71
3
208
5.24
<0.5
<0.5
60
<50
<0.03
<0.5 B
<0.5
450
<0.1
200
51.3
390
<0.1
314
5.8
NA
NA
NA
NA
NA
NA
BG-02
01/08/2016
6.4
31.23
17
588
0.9
-16
189
1.98
<1
<1
58
<50
<0.03
<1
<1
471
<1
196
50.6
350
<0.2
370
4.2
NA
NA
NA
NA
NA
NA
BG-02
04/04/2016
6.4
30.42
18
651
0.15
139
344
2.71
<1
<1
65
<50
<0.03
<5
<1
585
<1
237
56
391
<0.2
360
5
4.07
<3
<0.00005
<0.00005
<0.00005
0.00102
BG-02
07/13/2016
6.2
30.04
17
638
0.22
-51
154
3.4
<1
11
59
<50
<0.03
<5
<1
484
<1
207
53.3
374
<0.2
370
4.79
4.4
3.12
<0.00005
<0.00005
<0.00005
0.000918
BG-02
09/07/2016
6.7
30.04
18
635
0.14
-82
123
2.9
<1
<1
59
<50
<0.03
<1
<1
553
<1
194
53.5
378
<0.2
370
5.34
0.997
1<1
<0.00005
<0.00005
<0.00005
0.000791
MW-12D
06/24/2015
6.2
31.15
17
136
2.42
-1
204
4.02
1.63
<1
26
<50
NA
<1
1.37
326
<1
683
8.98
95
<0.2
120
0.719
NA
NA
NA
NA
NA
NA
MW-12D
06/25/2015
6.2
31.10
17
124
2.72
29
234
4.5
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-12D
09/10/2015
6.2
32.10
17
125
2.6
39
244
3.88
<1
<1
20
<50
NA
1.1
<1
277
<1
218
9.03
85
<0.2
100
0.637
NA
NA
NA
NA
NA
NA
MW-12D
1210212015
6.0
32.50
16
135
3.4
135
340
11.3
1.44
<1
21
<50
0.55
3.43
<1
504
<1
193
9.18
90
<0.2
97
1.01
NA
NA
NA
NA
NA
NA
MW-12D
12/04/2015
6.1
32.83
18
122
3.35
140
345
8.08
<0.5
<0.5
20
<50
0.64 MI
4.6
0.51
280
<0.1
160
9.56
85
<0.1
122
<1
NA
NA
NA
NA
NA
NA
MW-12D
01/07/2016
6.1
31.95K17
118
3.1
136
341
9.26
<1
<1
22
<50
0.52 M1
2.99
<1
968
<1
131
8.76
87
<0.2
82
1.65
NA
NA
NA
NA
NA
NA
MW-12D
04/05/2016
5.9
30.28125
3.45
120
325
9.9
<1
<1
21
<50
0.6
1.64
<1
385
<1
100
9.35
92
<0.2
120
1.06
6
<3
<0.00005
<0.00005
<0.00005
0.000233
MW-12D
07/11/2016
5.7
29.17134
2.91
60
265
9.35
<1
<1
17
<50
0.73
1.19
<1
223
<1
81
9.26
88
<0.2
98
0.898
2.62
<1
<0.00005
10.00005
<0.00005
0.0000919j
MW-12D
09/07/2016
6.3
30.35128
3.77
38
243
9.2
<1
<1
16
150
0.75
2.99
11
409
cl
64
9.05
83
<0.2
100
1.13
2.19
<1
<0.00005
<0.00005
<0.00005
0,000105j
Total Count of Valid Samples
27
27
26
26
26
26
10
26
IS
26
26
26
15
6
Bedrock
BG-01
10/31/2008
5.7
35.99
16
141
NM
NM
NM
NM
0.13
1.4
1040
6
NA
36.9
NA
65700
33.1
2270
NA
NA
0.35
189
NA
NA
NA
NA
NA
NA
NA
BG-01
0610412009
7.0
34.44
18
161
NM
NM
NM
NM
2.5
<3
155
<200
NA
4.7
NA
2100
12.9
131
NA
NA
<1
167
NA
NA
NA
NA
NA
NA
NA
BG-01
10/21/2009
5.3
36.55
16
102
NM
NM
NM
NM
4.2
<I
175
<200
NA
15.7
NA
4610
2.3
166
NA
NA
<1
146
NA
NA
NA
NA
NA
NA
NA
BG-01
0412212010
5.6
33.59
15
107
NM
NM
NM
NM
<10
<10
120
<50
NA
8.2
NA
2000
12
39
NA
NA
<50
17
NA
NA
NA
NA
NA
NA
NA
BG-01
12/06/2010
5.9
36.64
16
186
NM
NM
NM
10
<0.5
<5
105
<50
NA
15.3
NA
1080
<5
26.3
NA
NA
<0.1
126
NA
NA
NA
NA
NA
NA
NA
BG-01
0412012011
5.5
35.36
20
158
1.16
50
255
22.7
<0.5
<5
99.1
<50
NA
6.1
NA
701
<5
26.6
NA
NA
<0.1
135
NA
NA
NA
NA
NA
NA
NA
BG-01
07/11/2011
5.5
35.57
24
163
0.99
-71
134
24.2
<0.5
<5
101 B
<50
NA
40.1
NA
1040
<5
29.6
NA
NA
<0.1
117 B
NA
NA
NA
NA
NA
NA
NA
BG-01
11/03/2011
5.5
37.18
18
165
1.27
-103
102
3.84
<0.5
<5
95.4
<50
NA
7.9
NA
261
<5
8.9
NA
NA
<0.1
106
NA
NA
NA
NA
NA
NA
NA
BG-01
04/04/2012
5.6
36.01
21
168
0.93
-91
114
9.52
<0.5
<5
93
<50
NA
6.7
NA
388
<5
11.6
NA
NA
<0.1
107
NA
NA
NA
NA
NA
NA
NA
BG-01
07/09/2012
5.3
36.69
19
166
1.05
-64
141
9.32
<0.5
<5
101
<50
NA
20
NA
640
<5
21.6
NA
NA
<0.1
128
NA
NA
NA
NA
NA
NA
NA
BG-01
11/05/2012
5.4
37.45
17
166
0.89
178
383
9.45
<0.5
<5
101
<50
NA
<5
NA
526
<5
55.6
NA
NA
<0.1
123
NA
NA
NA
NA
NA
NA
NA
BG-01
04/10/2013
5.2
35.25
17
165
0.79
213
418
9.05
<1
<1
97
<50
NA
7
NA
323
<1
15
NA
NA
<0.2
130
NA
NA
NA
NA
NA
NA
NA
BG-01
07/09/2013
5.4
34.17
19
160
1.02
152
357
8.95
<1
<1
97
<50
NA
<5
NA
488
<1
48
NA
NA
<0.2
130
NA
NA
NA
NA
NA
NA
NA
BG-01
11/13/2013
5.5
34.42
15
160
1.3
256
461
8.2
<1
<1
95
<50
NA
<5
NA
412
<1
27
NA
NA
<0.2
130
NA
NA
NA
NA
NA
NA
NA
BG-01
04/01/2014
5.4
32.85
15
159
1.2
340
545
8.2
<1
<1
90
<50
NA
<5
NA
290
<1
14
NA
NA
<0.2
140
NA
NA
NA
NA
NA
NA
NA
BG-01
07/18/2014
5.5
32.12
19
158
1.4
232
437
6.68
<1
<1
93
<50
NA
<5
NA
325
<1
15
NA
NA
<0.2
140
NA
NA
NA
NA
NA
NA
NA
BG-01
11/12/2014
5.5
31.90
18
167
1.64
255
460
9.96
<1
<1
95
<so
NA
<5
NA
466
<1
25
NA
NA
<0.2
120
NA
NA
NA
NA
NA
NA
NA
BG-01
04/13/2015
5.5
30A6
17
154
1.2
296
501
8.9
<1
<1
90
<50
NA
<5
<1
409
<1
35
12.4
NA
<0.2
130
NA
NA
NA
NA
NA
NA
NA
BG-01
07/07/2015
5.6
29.86
18
151
1.6
113
8
SO
<1
<1
97
<50
NA
<5
<1
557
<1
23
11.8
NA
<0.2
130
4.94
NA
NA
NA
NA
NA
NA
BG-OS
09/10/2015
5.3
30.43
19
168
1.5
190
�395
7.83
<1
<1
91
<50
NA
<1
<
300BG-01
11/03/2015
6.930.00
20
14
9.3
7
2
1.79
<1
<1
90
<50
NA
<5
<1
45
<1
7
11.8 B2
179
<0.2
130
3.4
NA
NA
NA
NA
NA
NA
P:\Duke Energy Pmgress.1026\305. Mayo Ash Basin GW Assessment Plan\19.EG_CSASUP\Statistics\Background GW NovDec 2016\MAYO Background GW data through Sep 2016 Page 1 of 2

TABLE 1
BACKGROUND GROUNDWATER DATA SUMMARY THROUGH 2O16-09
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
pH
Water
Level
Temp
Spec
Cond
DO
ORP
Eh
Turbidity
Antimony
Arsenic
Barium
Boron
Chromium
(VI)
Chromium
Cobalt
iron
Lead
Manganese
Sodium
Strontium
Thallium
Total
Dissolved
Solids
Vanadium
Radium-226
Radium-228
Uranium-233
Uranium-234
Uranium-236
Uranium-238
Reporting Units
S.U.
ft
Deg C
umhos/cm
mg/L
mV
mV
NTUs
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
mg/L
ug/L
ug/L
mg/L
ug/L
pCi/L
pCi/L
ug/mL
ug/mL
ug/mL
ug/mL
15A NCAC 02L Standard
6.5-8.5
NE
NE
NE
NE
NE
NE
NE
1*
SO
700
700
0.07-
SO
1*
300
15
50
NE
NE
0.2*
500
0.3*
NE
NE
NE
NE
NE
NE
Sample ID
Sample
Collection Date
Field Parameters
Analytical Results
BG-01
12/05/2015
5.5
30.34
16
ISO
1.55
128
333
9.5
<0.5
<0.5
94
<50
0.31
1
<0.5
350
0.13
18
12.2
180
<0.1
118
4.2
NA
NA
NA
NA
NA
NA
BG-01
O1/08/2016
5.1
29.36
15
147
1.48
67
272
5.78
<1
<1
87
<50
0.2
<1
<1
272
<1
11
11.9
166
<0.2
130
3.94
NA
NA
NA
NA
NA
NA
BG-01
04/04/2016
5.5
28.46
17
149
1.58
206
411
4.3
<1
<1
88
<50
0.19 Ml
<5
<1
190
<1
12
11.5
167
<0.2
130
3.94
2.25
<3
<0.00005
<0.00005
<0.00005
<0.0002
BG-01
07/13/2016
5.0
28.42
19
148
1.64
85
290
3.84
<1
<1
86
<50
0.23
<5
<1
89
<1
7
11.9
177
<0.2
140
3.58
1.29
<1
<0.00005
<0.00005
<0.00005
<0.0002
BG-01
09/08/2016
5.5
28.98
18
147
1.61
148
353
9.49
<1
<1
90
<50
0.3
<1
<1
336
<1
13
11.7
172
<0.2
130
4.69
3.24
0.636
<0.00005
<0.00005
<0.00005
<0.0002
MW-10BR
0311712015
6.2
13.19
22
467
0.55
99
304
35.5
<I
<I
27
<50
NA
1.3
<I
883
<I
89-
37.9
210
<0.2
330
1.66
NA
NA
NA
NA
NA
NA
MW-10BR
09/11/2015
6.1
13.36
25
452
0.5
14
219
1.06
<1
<1
5
<50
NA
<1
<1
37
<1
L35
39.1
198
<0.2
310
1.73
NA
NA
NA
NA
NA
NA
MW-10BR
12/03/2015
6.1
13.30
16
424
0.4
19
224
1.5
<1
<1
<5
<50
<0.03
<1
<1
193
<1
84
37.7
198
<0.2
320
1.5
NA
NA
NA
NA
NA
NA
MW-IOBR
O1/07/2016
6.1
13.08
13
449
0.53
50
255
1.64
<1
<1
<5
<50
<0.03
<1
<1
33
<1
103
39.5
195
<0.2
300
1.68
NA
NA
NA
NA
NA
NA
MW-IOBR
04/05/2016
6.2
12.70
13
443
0.43
141
346
0.98
<1
<1
<5
<50
<0.03
<1
<1
29
<1
71
38.8
195
<0.2
300
1.7
0.989
1.77
<0.00005
<0.00005
<0.00005
0.000188j
MW-IOBR
07/13/2016
6.3
11.96
21
446
0.65
21
226
4.12
<1
<1
6
<50
0.041
<1
<1
24
<1
74
41.7
198
<0.2
310
2.01
0.9
0.518
<0.00005
<0.00005
<0.00005
0.0000755j
MW-10BR
09/07/2016
6.2
12.95
21
442
0.38
65
270
2.25
<1
<1
<5
<50
0.07
<1
<1
35
<1
72
38.2
208
<0.2
310
1.91
1.64
<1
<0.00005
<0.00005
<0.00005
<0.0002
MW-11BR
06/25/2015
8.1
40.25
19
382
2.79
28
233
3.91
1.32.
<1
44
<50
NA
1.73
<1
115
<1
67
14.3
200
0.323
250
2.69
NA
NA
NA
NA
NA
NA
MW-11BR
09/11/2015
9.2
36.86
21
282
1.1
33
238
7.87
1.74
1.06
32
<50
NA
15.6
<1
153
<1
1i
15.E
318
180
9.15
NA
NA
NA
NA
NA
NA
MW-11BR
12/03/2015
9.2
36.70
14
230
1.8
-10
195
8.7
1.57
1.05
22
<50
1 13.6
24.1
<1
304
<1
29
20.,
250
<0.2
ISO
12.1
NA
NA
NA
NA
NA
NA
MW-11BR
O1/07/2016
9.8
36.18
14
214
1.2
-40
165
5.04
1.9
1.02
24
<50
12.2
15.1
<1
98
<1
17
16.6
253
<0.2
130
12.7
NA
NA
NA
NA
NA
NA
MW-11BR
04/05/2016
10.3
35.21
15
208
1.28
154
359
6.43
1.6
<1
25
<50
18.4
17.2
<1
178
<1
25
16.5
256
<0.2
140
14.5
0.33
<3
<0.00005
<0.00005
<0.00005
0.000351
MW-11BR
07/13/2016
10.6
34.99
18
262
0.94
-99
106
7.54
1.48
<1
27
<50
12.5
14.5
<1
104
<1
15
17-
278
<0.2
140
15.6
<1
<1
<0.00005
<0.00005
<0.00005
0.00025
MW-IIBR
09/06/2016
10.8
36.44
20
248
1.44
-77
129
7.47
1.76
<1
27
<50
19.4 M6
15.5
<1
146
<1
10
16.1
276
<0.2 B2
110
13.9
<1
0.785
-0.00005
<0.00005
<0.00005
0.00018j
MW-13BR
06/23/2015
7.2
31.28
21
580
0.4
-228
-23
2.22
<1
<1
40
<50
NA
<1
1.19
1130
<1
474
25.7
418
<0.2
370
0.381
1.22
<3
<0.00005
<0.00005
<0.00005
<0.0002
MW-13BR
09/08/2015
6.9
31.63
23
579
0.5
-136
69
7.55
<1
<1
51
<50
NA
<1
<1
2400
<1
630
24.8
430
0.538
360
0.465
NA
NA
NA
NA
NA
NA
MW-13BR
12/02/2015
7.0
31.55
16
543
0.3
-130
75
6.5
<1
<1
45
<50
<0.03
16.3
<1
2490
<1
548
23.3
416
<0.2
330
0.429
NA
NA
NA
NA
NA
NA
MW-13BR
O1/07/2016
7.3
30.36
11
544
0.5
-75
130
7.79
<1
<1
42
<50
<0.03
7.65
<1
12550
1 <1
519
23.7
389
<0.2
330
<0.3
NA
NA
NA
NA
NA
NA
MW-13BR
04/05/2016
7.1
29.70
15
566
0.3
151
356
9.05
<1
<1
35
<50
<0.03
<1
1.01
1750
<1
481
20.8
393
<0.2
340
<0.3
2.65
<3
<0.00005
<0.00005
<0.00005
0.000629
MW-13BR
07/11/2016
7.0
28.68
19
553
0.19
-89
116
8.8
<1
<1
29
<50
<0.03
4.51
1.92
1330
<1
348
19.4
380
<0.2
330
0.871
2.33
0.773
<0.00005
<0.00005
<0.00005
0.00188
MW-13BR
09/06/2016
7.4
29.77
21
554
0.42
-163
42
9.67
<1
<1
38
<50
<0.03
2.02
1.17
2520
<1
432
18.4
381
<0.2 B2
330
<0.3
67.2
<1
<0.00005
<0.00005
'0.00005
0.000451
MW-14BR
0311212015
6.7
16.20
14
278
0.47
41
224
35
<I
<1
30
<50
NA
11
1.41
907
<1
54,
33
149
<0.2
190
1.29
NA
NA
NA
NA
NA
NA
MW-14BR
09/09/2015
6.9
18.03
22
413
1.1
-16
189
3.36
<1
1.8
42
65
NA
<1
1.09
2730
<1
648
60.2
167
<0.2
260
0.469
NA
NA
NA
NA
NA
NA
MW-14BR
12/02/2015
6.7
16.54
15
282
1 0.57
26
231
2.77
<1
<1
1 22
1 <50
<0.03
<1
<1
396
<1
1304
41.6
141
<0.2
210
1.82
NA
NA
NA
NA
NA
NA
MW-14BR
O1/07/2016
6.7
16.31
11
258
2.73
64
1 269
2.45
<1
<1
17
<50
<0.03
<1
<1
98
<1
199
37.4
131
<0.2
180
2.45
NA
NA
NA
NA
NA
NA
MW-14BR
04/05/2016
6.7
16.27
14
261
2.13
220
425
2.45
<1
<1
19
<50
<0.03
<1
<1
89
<1
196
38.4
134
<0.2
200
2.86
0.999
<3
<0.00005
<0.00005
<0.00005
0.000241
MW-14BR
07/11/2016
6.7
15.35
20
311
0.23
90
295
1.34
<1
<1
22
<50
<0.03
<1
<1
37
<1
247
47.9
140
<0.2
200
2.48
0.947
<1
<0.00005
<0.00005
<0.00005
0.000456
MW-14BR
09/07/2016
6.7
17.61
18
324
0.24
21
226
5.69
<1
<1
28
<50
<0.03
<1
<1
56
<1
322
46.3 M4
168
<0.2
230
2.07
2
<1
<0.00005
<0.00005
<0.00005
0,000314
Total Count of Valid Samples
44
44
44
44
34
44
Mpr
16
36
16
16
Prepared by: RKD Checked by: JAW
Notes:
Red text indicates samples not used in determination of provisional preliminary background threshold values (PPBTVs) -eliminated due to pH > 8.5 or turbidity > 10 NTU or or pH and/or turbidity not measured
Green text indicates well completed in bedrock with expected naturally occuring high pH. Additional evaluation of bedrock is underway to verify naturally occuring pH values. Values are retained for background statistical analysis at this time.
O = Bold highlighted concentration indicates exceedance of the 15A NCAC 02L .0202 Standard, the IMAC, or the NC DH HIS Screening Level for chromium VI. (Effective date for 15A NCAC 02L.0202 Standard and IMAC is April 1, 2013)
Spec Cord = Specific Conductance R = Feet umhos/cm = Micro mhos per centimeter Temp = Temperature NTU = Nephelometric turbidity unit pCi/I = picocuries per liter
S.U. = Standard Unit NA = Not analyzed mg/L = Milligram per liter DO = Dissolved oxygen NE = Not established NM = Not measured
Eh = Redox Potential Deg C = Degrees Celsius mV = Millivolts ORP = Oxidation -Reduction Potential ug/L = Microgram per liter ug/mL = microgram per milliliter
= NC DHHS Health Screening Level
< = Concentration not detected at or above the reporting limit
= Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013.
B2 = Target analyte was detected in blank(s) at a concentration greater than 1/2 the reporting limit but less than the reporting limit. Analyte concentration In sample Is valid and may be used for compliance purposes.
j = Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit.
M1 = Matrix spike recovery was high: the associated Laboratory Control Spike (LCS) was acceptable.
M4 = The spike recovery value was unusable since the analyte concentration in the sample was disproportionate to the spike level.
M6 = Matrix spike and Matrix spike duplicate recovery not evaluated against control limits due to sample dilution.
P:\Duke Energy Progress.1026\305. Mayo Ash Basin GW Assessment Plan\19.EG_CSASUP\Statistics\Background GW NovDec 2016\MAYO Background GW data through Sep 2016 Page 2 of 2