Riverbend Soil Background Tech Memo REV1_20170526

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Technical Memorandum
Date: Friday, May 26, 2017
Project: Riverbend Steam Station
To: Sean DeNeale
From: Jacob Ruffing
Subject: Quantification of Valid Background Soil Samples for Statistical Calculations — Revision 1
The purpose of this revised technical memorandum (TM) is to address the North Carolina Department of
Environmental Quality's (NCDEQ's) requirement identified below. In addition, this revised TM provides the
basis for evaluation of soil samples proposed for use in determining site -specific background
concentrations using statistical methods for the Riverbend Steam Station (RBSS) as originally presented
in the TM dated December 13, 2016.
Following submittal of the TM dated December 13, 2016, Duke Energy submitted the Statistical Methods
for Developing Reference Background Concentrations for Groundwater and Soil at Coal Ash Facilities
(Background Methodology) to NCDEQ on January 20, 2017. NCDEQ subsequently requested additional
information regarding the Background Methodology via a letter dated April 28, 2017. As part of the April
28, 2017 letter, NCDEQ requested the following information:
Provide up-to-date digital spreadsheets of raw background soil data for each facility by May 26,
2017. Any soil data collected since submittal of the Comprehensive Site Assessments (CSAs)
should be included in the table and existing soil data should be reviewed to identify any quality
control issues (i.e., sampling intervals, corresponding boring sample ID, etc.) along with
identification of outliers and revised accordingly.
The up-to-date raw background soil data for background determinations at RBSS are provided in Table 1
of this revised TM. Note the remainder of the requirements in the April 28, 2017 NCDEQ letter are
addressed in a revision to the Background Methodology under separate cover.
The soil samples evaluated herein were principally collected during CSA fieldwork conducted between
March and July 2015. The locations of soil samples to be evaluated for use in the background
determinations are shown on Figure 1.
Viability of samples for use in developing background concentrations was evaluated using the following
criteria:
• Soil sample is collected from a location that is not impacted by coal combustion residuals or coal -
associated materials;
• Soil sample is collected from a location that is not impacted by other potential anthropogenic
sources of constituents;
• Soil sample is collected from the unsaturated zone, above the maximum groundwater elevation
measured in shallow wells during seven well gauging events conducted between July 2015 and
September 2016; and
0 Soil sample collected from a location not impacted by periodic flooding.

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A total of 69 soil samples were collected at Riverbend during CSA activities. Of these 69 samples, 28
samples satisfy the four criteria listed above and are considered viable samples for use in statistical
calculations. These samples were collected from the following locations on -site: BG-1 D, BG-21D, BG-3D,
GWA-21D, GWA-31D, GWA-51D, GWA-61D, GWA-7D, GWABD, GWA-91D, GWA-10S, GWA-20D, GWA-21 D,
GWA-221D, GWA-23D, MW-7BR, MW-15D, OB-1, and OB-2. Note that viable samples collected from
borings near the waste boundary or down -gradient of ash management areas were collected at least one
foot above the maximum measured groundwater elevation and are assumed to have not been impacted
by groundwater migrating from ash sources.
Soil sampling data used in this evaluation, including the range of groundwater elevations for shallow wells
in each well cluster and analytical results of soil samples are provided in Table 1. Note that laboratory
reporting limit for antimony, arsenic, boron (one sample), cobalt, selenium, and thallium exceeded the
North Carolina Protection of Groundwater (POG) Preliminary Soil Remediation Goals, as revised in
October 2016.

/
MW-15
/MW-15D
MW-15BR
MW-12*
S-4/GWA-10
®
S-4
GWA-10S
/
GWA-10BRU
Q- Qom- ,yam
S-9
MW-3S
MW-3D
}GWA-IS S-5
vQ==
GWA-1BRU
! '�Q o�
T
MW-11SR •
BMW-11DR
p Q r
-1
Q�
M W-2S*
S-3 MW-2S-A
MW-2D
GWA-2S
GWA-2BRU
/ VGWA-2BR
/ MW-10
l �S-1/S-2 MW-1S
A ` IN, J•� J MW-1D AB-5S*
alo� AB-5SL*
AB-6S AB-5D*
Q QEF� I I AB-6BRU
PRO MW-9 S-1
{�.MW-9D
GWA-3S* I J MW-9BR
GWA-3S-A A13-8S
GWA-3D GWA-15S
GWA-313R GWA-15D
AB-8D
• SW-3
GWA-11D
C-113RUO
GWA-11S
C-1S
C-2S
C-2D
CINDER
STORAGE
ASH STORAGE
GWA-12S
GWA-12D
AS-2S*
AS-2D*
AS -IS*
AS -ID*
GWA-23BR
GWA-23S
GWA-23D
GWA-4S
OGWA-4D
GWA-4BR
RBSW003 RIVERBEND
RBSWO01 STEAM STATION
BG-4S BG-41)
BG-4BR 1
A \ 1
1
BG 5 R
O
NOTES:
1. PARCEL DATA FOR THE SITE WAS OBTAINED FROM DUKE ENERGY REAL ESTATE AND IS APPROXIMATE.
2. ASH STORAGE BOUNDARY AND CINDER STORAGE BOUNDARY ARE APPROXIMATE.
3. AS -BUILT MONITORING WELL LOCATIONS PROVIDED BY DUKE ENERGY.
4. SHALLOW MONITORING WELLS (S) - WELL SCREEN INSTALLED ACROSS THE SURFICIAL WATER TABLE.
5. SHALLOW LOWER MONITORING WELLS (SL) - BOTTOM OF WELL SCREEN SET AT THE ASH-REGOLITH INTERFACE.
6. INTERMEDIATE MONITORING WELLS (1) - WELL SCREEN INSTALLED IN REGOLITH BELOW WATER TABLE AND BELOW ASH IN ASH BASIN.
7. TOPOGRAPHY DATA FOR THE SITE WAS OBTAINED FROM NC DOT GEOGRAPHIC INFORMATION SYSTEM (GIS) WEB SITE.
8. ORTHOPHOTOGRAPHY WAS OBTAINED FROM WSP (DATED APRIL 2014).
9. THE COMPLIANCE BOUNDARY IS ESTABLISHED ACCORDING TO THE DEFINITION FOUND IN 15A NCAC 02L .0107 (a).
10. HYDROGRAPHY WAS OBTAINED FROM USGS 7.5-MINUTE SERIES TOPOGRAPHIC MAPS MOUNTAIN ISLAND LAKE, NC.
AS-3SA*
AS-3D*
ASH BASIN
SECONDARY CELL
l
MW-4D� OGti T,9 O
M W-13 �Fc5l
pA�
MW-5D 0��� IrF
�AB 1D � \
S-10 1 \
S-11 ►� \ `�
• S-10/S-12
M W`S,S
MW- D
AB-2S0- 0 S-12 ( \.
AB-21)
GWA-9S
GWA-9D \
AB-4S*
GWA-913R
-�
AB-4D*
MW-14 -
S-6 \
SW-2
v
oGWA-8S
GWA-8D
AB-3S*
F
AB-3D*
f S-13 I
ASH BASIN
AB-3BR*
OBG-3S
PRIMARY CELL
w
•a d r2 t '. ti
'`
GWA-7S
a�
GWA-713R
BG-2S /
1;�,BG-2D
013-1 OB-2
BG-2BR
AB-7S*
AB-71
/'•,
AB-7D*
M W-7S*
/
GWA-6S .
MW-7BR
7
GWA-6D
MW-71)
MW-7SR
/
.� BG-1S
BG-ID
GWA-14S
/
GWA-5SL
GWA-14D
GWA-5D
GWA-22S HORSES OH E BE D BEACH ROAp i
GWA-20S G WA-22 D
GWA-20D �, MW-85
GWA-20BR MW-8D GWA-22BR-A \ I
MW-81 GWA-21S,
GWA-211) '` \
GWA-13S GWA-21BR
GWA-13D
Y ir
y !. '� • r-. ` _ + ,., r "rGy`• �k tbra" _
r
ey
-r
4
y^ xF�_ _
SCALE (FEET)
200' 0 200' 400'
I" = 400'
ABANDONED WELLS
WELL ID
NORTHING
EASTING
AB-3BR
593978.52
1415271.06
AB-313
593974.72
1415275.76
AB-3S
593982.21
1415267.15
AB-413
594396.84
1414855.06
AB-4S
594393.61
1414857.36
AB-513
593709.72
1414280.27
AB-5S
593710.50
1414273.99
AB-5SL
593711.23
1414269.22
AB-713
593068.71
1415045.58
AB-7S
593047.91
1415046.88
A B-7S I
593054.54
1415045.99
AS-1D
592498.83
1413188.18
AS-1S
592513.58
1413205.28
AS-2D
592600.94
1413757.51
AS-2S
592617.99
1413760.43
AS-3D
592656.95
1414310.71
AS-3S
592637.18
1414312.33
GWA-3S
593361.15
1412342.59
MW-2S
595037.80
1414508.00
MW-7S
592781.00
1415852.00
MW-12
595927.30
1414835.00
* DENOTES THAT WELL HAS BEEN ABANDONED
LEGEND:
DUKE ENERGY PROPERTY BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY COINCIDENT
WITH DUKE ENERGY PROPERTY BOUNDARY
ASH BASIN WASTE BOUNDARY
ASH OR CINDER STORAGE AREA BOUNDARY
STREAM
ASH BASIN COMPLIANCE
GROUNDWATER MONITORING WELL
ASH BASIN VOLUNTARY
GROUNDWATER MONITORING WELL
CSA GROUNDWATER MONITORING WELL
POST-CSA ADDITIONAL ASSESSMENT
GROUNDWATER MONITORING WELL
ABANDONED WELL
OBSERVATION WELL (WATER LEVEL ONLY)
SURFACE WATER SAMPLE LOCATION
AREA OF WETNESS SAMPLE LOCATION
NCDENR SAMPLE LOCATION
SAMPLE LOCATION MAP DATE
CAMA AND NPDES PROGRAMS mnvzon
DUKE ENERGY CAROLINAS, LLC
RIVERBEND STEAM STATION ASH BASIN FIGURE
cAsoN roUri-Y. NORTH r_;aRouN= �

Table 1. Analytical Results
Analyte
Aluminum
Antimony
Arsenic
Barium
Boron
Beryllium
Cadmium
Chromium
Cobalt
Copper
Iron
Lead
Manganese
Mercury
Molybdenum
Nickel
Selenium
Strontium
Thallium
Vanadium
Zinc
Calcium
Chloride
Magnesium
Nitrate
Nitrogen
Potassium
Sodium
Sulfate
pH (field)
Total
Organic
Carbon
CAS RN
7429-90-5
7440-36-0
7440-38-2
7440-39-3
7440-42-8
7440-41-7
7440-43-9
7440-47-3
744048-4
7440-50-8
7439-89-6
7439-92-1
7439-96-5
7439-97-6
7439-98-7
7440-02-0
778249-2
7440-24-6
7440-28-0
7440-62-2
7440-66-6
7440-70-2
16887-00-6
7439-96-4
14797-55-8
7727-37-9
7440-09-7
7440-23-5
14808-79-8
PH
TOC
Result Unit
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mglkg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
g /k m g
mgIkg
mg g
glkg
mgIkg
mgIkg
mgtkg
mg g
gIkg
mgtkg
glkg
nngIkg
glkg
Bid. Units
mglkg
NCDEQ PSRG Intl
100000
94
3
44000
46000
460
200
100000
70
9400
100000
800
5200
8
1200
4400
1200
100000
2.4
1200
70000
NS
NS
NS
100000
NS
NS
NS
NS
NS
NS
NCDEQ PSRG POG
NS
0.9
5.8
580
45
63
3
360000
0.9
700
150
270
65
1
NS
130
2.1
NS
0.28
6
1200
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
Sample Name
Sample Date
Range of Deptli
Water (ft)
BG-1D (5-6)
6/3/2015
26.26-32.00
12100
6S14
6:6-k1
20.4
16.2 U
0.32 U
0.78 U
9
65N
11.6
32200
13.7
29.1
0.048
3.2 U
1.3 J
6iU
3.2 U
6SU
89.2
6.5 U
162 U
321 U
162 U
NA
32A UJ
325 U
325 U
321 U
4.6 J
448 J
BG-1 D (14-15)
6/3/2015
26.26-32.00
11600
8311
83k1
77.3
20.7 U
0.41 U
0.99 U
5.5
5 J
15.1
26800
4.9 J
226
0.0095 J
4.1 U
3.4
8-3-U
4.1 U
8-W
70.2
12.5
207 U
427 U
2750
NA
42.7 UJ
2580
414 U
427 U
5.6 J
1020 U
BG-1 D (24-25)
6/3/2015
26.2632.00
14100
6-2-U
9-211
175
20.5 U
0.25 J
0.98 U
5.4
22.8
25.2
28200
6 J
1140
0,013 U
4.1 U
6.4
8-2-U
4.1 U
6-2-U
75.8
34.7
205 U
394 U
7340
NA
39.4 UJ
6500
410 U
394 U
5 J
970 U
BG-2D (3.5-5)
6/13/2015
50.37-53.55
15700
64JJ
5.5 J
17.7 J
15.3 U
0.2 J
0.73 U
33
64-J
8.1
36500
10.9
1 L4
0.55 J-
3.1 U
1.5 U
6,4-t1
3.9
9 -U
89.2
7.7
451
301 UJ
308
NA
30.1 UJ
1920
306 U
175 J-
6.1 J
1640 J-
BG-2D (48-49)
6/15/2015
50.37-53.55
10700
6311
6.344
161
15.8 U
0.63
0.76 U
6
14.6
5.3
17100
15.2
290
0.01 UJ
3.2 U
4.5
63-U
7.2
82-U
43.9
45.7
NA
NA
NA
NA
31A UJ
NA
NA
NA
4.5 J
749 UJ
BG-3D (3-5)
6/13/2015
25.24-28.34
23100
63-U
6.3k1
28.4
15.7 U
0.33
0.75 U
17.4
63-U
11.4
34100
18.1
114
0.027 J+
3.1 U
6.7
63-U
1.7 J
6.3U
67.5
24.6
157 U
313 U
526
31.3 U
NA
586
314 U
313 U
4.8 J
555 J
BG-3D (18.5-20)
6/13/2015
25.24-28.34
26000
6- -u
64U
240
15.4 U
0.66
0.74 U
14A
14.6
16.4
23800
4.2 J
943
0.01 U
3.1 U
8.3
64-U
10.4
64-U
62.3
43
1150
309 U
8030
30.9 U
NA
6450
307 U
309 U
6 J
752 U
BG-3D (23-24)
6/13/2015
25.24-28.34
26700
6.2U
6.21J
276
15.6 U
0.84
0.75 U
6.1
11
10.4
18100
3.7 J
626
0.01 U
3.1 U
7.6
6.2U
16.2
6.2U
45.4
45.8
1420
NA
7660
31.8 U
NA
6410
311 U
NA
5.8 J
765 U
GWA-2D (30.0-31.5)
4/13/2015
40.91-46.04
31100
79-U
7.8 U
26.1
0.98
0.94 U
1.3 J
18.8
5.3
39700
7.8 U
1560
0.012 U
3.9 U
14.6
7.8-U
33.2
73-U
128
149
3330
382 U
23200
NA
38.2 UJ
10400
391 U
382 U
5.8 J
740 U
GWA-3D (18.5-19)
4/21/2015
27.05-29.53
3450
54W
5.8 U
25.6
14.5 U
0.29 U
0.7 U
4.5
54-U
1.4 UJ
5320
5.8 U
155
0.0087 UJ
2.9 U
2.9
5-"
4.4
6.8-41
11.5
14.7
843
271 UJ
2360
NA
27.1 UJ
1960
290 U
271 UJ
7.2 J
NA
GWA-5D (58.5-60)
4/10/2015
61.56-74.90
3340
6-9-U
6.8kJ
28.7
17.2 U
0.22 J
0.83 U
3.2
13.5
7.1
18600
4.5 J
477
0.011 U
3.4 U
1.7 U
63U
3.4 U
6.9-u
33.6
6.8 J
172 U
341 U
172 U
NA
34.1 UJ
344 U
344 U
341 U
5.2 J
821 U
GWA-6D-1 (43.545)
3/4/2015
50.13-53.78
2380
34-U
3.4 U
75.5
14.9
0.29 J
0.41 U
7.3 J+
25.4
23.2
19000
4.6
1270
0.01 U
0.68 U
4.2 J+
3.4 U
0.68 U
34JJ
55.8
3.6 J+
34.1 U
353 U
92.1 J+
NA
35.3 UJ
105 J+
68.1 U
353 U
5.4 J
848 U
GWA-6D-2 (48.5-50)
3/4/2015
50.13-53.78
13200
44U
4.4 U
176
16.2
0.3 J
0.53 U
1.2 J+
10.5
28.1
18200
2.6 J
623
0.01 U
0.89 U
2.4 J+
4..4-U
21.8
44-W
55.5
56.7 J+
4250
446 UJ
8830
NA
44.6 UJ
8320
156 J+
446 U
5.5 J
1070 U
GWA-75 (ZO-8.0)
4/21/2015
11.10-18,80
8390
6.7-11
6.�U
117
16.7 U
0.33 U
0.8 U
53A
73.8
51.8
58900
4.9 J
1700
0.045
3.3 U
3.2
6.7-U
6.6
6311
209
25.2
545
326 U
487
NA
32-6 UJ
334 U
334 U
326 U
6 J
1020
GWA-8D (8.5-10)
6/1/2015
12.89-23.81
8480
6.&U
6.4U
18.1
82.7 U
0.25 J
0.79 U
131
87
49
54200
6.6 U
959
0.063
3.3 U
37.2
6,6U
1.9 J
6§U
80.1
8.6
90 J+
325 U
615 J+
NA
32.5 UJ
331 U
331 U
325 U
5 J
457 J
GWA-9D (1)
5/5/2015
3.11-4.36
20300
7-U
7U
105
17.5 U
0.5
0.84 U
52.1
38.7
55.5
62500
7 U
1560
0.034
3.5 U
17.8
7- 4
6.1
7U
143
25.7
459
358 U
975
NA
35.8 UJ
346 J
349 U
358 U
4,9 J
5860
GWA-10S (8-9)
6/17/2015
10.78-12.22
14000
Z.4U
'�
57.6
17.8 U
0.32 J
0.85 U
12.3
24A
18.6
30100
5.9 J
1840
0.063 J-
3.6 U
3
ZA-U
2.4 J
Z.4U
59.3
16.5
134 J
342 U
1520
NA
34.2 UJ
389
355 U
342 U
4.1 J
974 J-
GWA-20D (40-41.5)
6/14/2015
43.07-47.82
6540
6A-k1
6-4-u
12.4
16 U
0.33
0.77 U
4.4
64-U
2.7
9880
6.4 U
131
0.011 U
3.2 U
2.3
6.4-t1
3.2 U
6 4-W
19
7.1
116 J
325 U
457
32.5 U
NA
182 J
321 U
325 U
4.8 J
795 U
GWA-21 D (3.5-5)
7/15/2015
59.33-66.53
37400
B.bU
12.2
37.7
21.4 U
0.41 J
1 U
62.4
6:6U
7.6
64000
20.9
153
0.54
4.3 UJ
3.5
85U
7.1
6SU
NA
17.3
379
402 U
232
40.2 UJ
NA
275 J
427 U
402 U
5 J
9440
GWA-21 D (8.5-10)
7/16/2015
59.33-66.53
5430 J+
5-9U
3.6 J
2.5 J+
14.8 UJ
0.3 U
0.71 U
17.7 J+
5:9-U
5.2 J+
38300
3.2 J
92.7
0.0077 J
3 UJ
1.5 UJ
5SU
3 UJ
5-:g-U
NA
5.9 UJ
NA
NA
NA
29.4 UJ
NA
NA
NA
NA
5 J
603 J
GWA-21 D (18.5-20)
7/16/2015
59.33-66.53
4250
74U
74U
3.7 UJ
18.4 U
0.44
0.88 U
16.9 J+
5.3 J
7.9 J+
26600
7.4 UJ
68.4
0.0098 J
3.7 UJ
10.2
7411
3.7 UJ
74 t
NA
35.5 J+
184 UJ
369 U
184 UJ
36.9 UJ
NA
368 UJ
368 UJ
369 U
5 J
897 U
GWA-21 D (48.5-50)
7/18/2015
59.33-66.53
2070
6.2-U
6-W
113
15.7 UJ
0.24 J
0.75 U
3.2
4.5 J
16
14300
6.3 U
592
0.01 UJ
3.1 UJ
2.9
63-U
3.1 U
6.8k1
NA
20.2
NA
NA
NA
30.2 UJ
NA
NA
NA
NA
5.2 J
741 U
GWA-22D (38.540.0)
5/7/2015
46.20-52.62
4130
7,7-U
7.711
24.7
19.2 U
0.38 U
0.92 U
4
7311
9.9
7160
7.7 U
77.7
0.012 U
3.8 U
1.9 U
77-U
3.8 U
7-.7-U
7 J
7.7 U
192 U
369 U
193
NA
36.9 UJ
216 J
384 U
369 U
5.1 J
884 U
GWA-23D (33.5-35)
5/12/2015
37.28-41.29
3140
6-5-U
6.6k1
27.6
16.3 U
0.33 U
0.78 U
1.6 UJ
6_9
2
5230
5 J
336
0.01 UJ
3.3 U
1.1 J
65-U
3.3 U
65U
9_9
3.8 J+
163 U
338 UJ
147 J
NA
33.8 UJ
325 U
325 U
338 UJ
4.6 J
795 UJ
MW-7BR (43.545)
4/24/2015
50.50-52.79
5650 J
6A-W
6A-UJ
31.3
12 J
0.32 U
0.77 U
3.6
7.3 J
4.5
12300 J
3.7 J+
446 J
0.01 U
3.2 UJ
2.4
NA
3.2 U
64-U
29.2
6.6
160 U
323 U
620
NA
32.3 UJ
216 J+
321 U
323 U
5.4 J
780 UJ
M W-15D (3.5-5)
4/29/2015
9.56-10.90
24000
7.9-u
7:J-u
66.5
40.1
0.88
0.95 U
30.1
6.6 J
22.5 J+
48800
17.8
335
0.011 J
4 U
7.4
791U
4.5 J+
7:gU
118
37.4
194 J+
381 U
1720 J+
NA
38.1 UJ
1430
397 U
381 U
5.3 J
1670 J-
QB4 (33.5-35.0)
4/16/2015
38.27-41.43
3580
721J
7,2-u
28.8
18 U
0.42
0.87 U
7.9
17.1
31.1
27400
7.2 U
905
0.011 U
3.6 U
1.8 U
734J
3.6 U
7.2-u
91
6.8 J
180 U
352 UJ
180 U
NA
35.2 UJ
361 U
361 U
352 UJ
5.1 J
844 U
OB-2 (38.5-00.0)
4/14/2015
44.13-46.41
14400
95U
95U
157
26.7
1.2
1.1 U
2.7
36.1
76.4
41000
9.5 U
1950
0.015 U
4.7 U
11.4
8.5-U
3 J
g3-u
130
60:8
155 J
488 U
4330
NA
48.8 UJ
2440
474 U
488 U
5.5 J
922 U
Total Number of Viable Soil Samples »
28
0
7
28
28
28
28
28
20
28
28
28
28
28
28
28
1
28
0
28
28
28
28
281
28
1 28
1 28
28
1 28
1 28
28
General Notes:
Depth -to -Groundwater data was collected in: 7/15, 9115, 11/15, 12/15, 3/16, 6/16, 9/16, and 3/17 (month/year)
"Strike-thmughs" indicates samples that will not be used in the initial background dataset for determining proposed provisional background threshold values (PPBTVs)
The criteria for "spike-throughs" (as stipulated by NCDEQ) requires Duke Energy to omit samples resulting in non -detect values higher than the Provisional Soil Remediation Goal for Protection of Groundwater
mg/kg - milligrams per kilogram
NA - Not analyzed or not reported by analytical laboratory
Sid. Units - pH units
Comparison Criteria:
NS - No applicable standard for this parameter
Shading indicates exceedance of either applicable criteria.
bold - indicates exceedance of NCDEQ Industrial Health Based PSRG
Italidunderline- indicates exceedance of NCDEQ Protection of Groundwater PSRG
North Carolina Department of Environmental
Quality Division of Waste Management Soil
Remediation Goals Table (October 2016) -
Preliminary Industrial Health Based Soil
Remediation Goal (PSRG) and Protection of
Groundwater PSRG.
"`Note: No PSRG for Total Chromium is
currently available, as a surrogate the PSRG
for Trivalent Chromium was used for
comparison purposes only.
Qualifier Notes:
U -- Not detected above the reporting detection limit.
J - Estimated concentration
J+-- Estimated concentration, biased high.
J--Estimated concentration, biased low.