NC0004979_Seep Monitoring Information_20141015

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Seep Monitoring Information

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RECEIVED/DENRIDWR
I Allen Steam Station OCT 1 5 2014
Surface Water and Seep Monitoring
1 August and September 2014 pe aam;ngg18s'e�n
IIntroduction
Flow and water quality measurements were collected from nine seep sampling locations (S-1 through S-
' 9)and two surface water locations near the ash basin (Lake Wylie-Upstream and Lake Wylie-
Downstream)associated with Duke Energy's Allen Steam Station, located in Gaston County, North
Carolina. The purpose of the sampling, which was conducted in late August and early September 2014,
Iwas to measure seepage flows and provide sufficient depth to allow collection of water quality samples for
laboratory analysis. Samples were collected via a combination of methods as described below. See
Figures 1 and 2 for maps of the approximate sampling locations. Descriptions of the seep sampling
locations are provided in Table 1.
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Seep Flow Measurement Method and Results
I A V-notch weir apparatus was utilized at locations S-1, S-2, S-3, and S-4 to impound the seepage in a
channel, which concentrated discharge to a central location that allowed for flow measurements to be
obtained.The weirs were constructed from 1/4-inch-thick Plexiglas board material. Each device was
I inspected after installation and prior to sampling to confirm sufficient flow and depth for sampling, and to
verify that only minimal leakage, if any, was present. Sufficient time was allowed for the impounded
seepage flows to reach equilibrium discharge flow before flow measurement and sampling.
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Flow measurements at seep sampling locations S-5, S-6, and S-7 were collected by installing a 2-inch-
diameter PVC pipe into the ground surface where the seep emerged. Seepage in these locations was
I diffuse, with no defined channel. Each PVC pipe was inserted in the location to direct flow through the
pipe. Flow from the pipe was observed until the discharge appeared to be clear of visible fines prior to
sampling for water quality analysis.
IFlow measurements at locations S-8 and S-9 were collected from two outfalls consisting of 12-inch-
diameter corrugated metal pipes (CMP). Based on a conversation with Duke Energy personnel familiar
I with the site, the source of water discharging from these pipes is unknown. These outfalls exhibited flow
during a dry-weather visual assessment consisting of least 72 hours prior to a rainfall event. The source
of persistent flow from these outfalls is assumed to be groundwater and not stormwater.
IThe seepage flows at locations S-1 through S-9 were measured using the timed-volumetric method.A
volume of water was collected from the discharge of the weir directly into an appropriately sized container.
Volumes(in mL)were measured in the field utilizing a graduated container. The amount of time(in
I seconds)needed to collect the volume of water was recorded and flows (in MGD)were calculated for the
timed-volume. The calculated flows(in MGD)at each seep location are presented in Appendix A.
ISeep Water Quality Sample Collection Method and Results
Water quality samples were collected at locations S-1 through S-9.To minimize potential effects of
Istormwater runoff, seep samples were collected during a period with minimal preceding rainfall. Samples
were collected from the discharge flow at the flow measurement devices described above or directly
from the seep into sample bottles while minimizing disturbance and entrainment of soil/sediment.
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Analytical parameters for analysis were:TSS, TDS, Oil&Grease, CI, SO4, F, COD, Al, As, B, Ba, Ca, Cd,
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' Cu, Cr, Fe, Mn, Mo, Mg, Ni, Pb, Sb, Se, TI, Zn, Hardness, and Hg. Storage and preservation techniques
of the samples, after collection and prior to analyses, were followed according to Appendix B. Analyses
were conducted by Duke Energy's Huntersville analytical laboratory(NC Wastewater Certification#248)
and Pace Analytical Laboratories(NC Wastewater Certification# 12). Laboratory analytical methods used
for each parameter are provided in Table 2 and analytical results are presented in Appendix A.
Seep In-situ Measurement Method and Results
In-situ field parameters (temperature, pH, and specific conductance)were measured at locations S-1
through S-9 utilizing calibrated field meters either at the discharge of the seep directly, at the discharge of
' the flow measurement devices, or in the water pool created behind the device, if sufficient water depth did
not exist at the device discharge.The analytical results are presented in Appendix A.
' Lake Wylie Water Quality and In-situ Sample Collection Method and Results
Water quality samples and in-situ measurements from were collected at a location upstream (Lake Wylie-
Upstream) and downstream (Lake Wylie-Downstream)of the ash basin(Figure 2). The grab samples
were collected from the surface(0.3 m)directly into appropriate sample bottles. Preservation and
analyses methods for the lake samples are provided in Table 2 and Appendix B. The analytical results are
' presented in Appendix A.
Recommendations
The low volume of flow at each seep location, coupled with the relatively low constituent concentrations in
the samples, suggests that there is little potential for Allen Steam Station to influence water quality in Lake
Wylie. If reasonable potential analyses demonstrate that there is no potential to exceed water quality
standards, then Duke Energy proposes to re-evaluate the seep locations listed in this document annually
over the next 5-year permit cycle. These annual evaluations would be documented and would verify the
condition of the existing seeps and determine the presence of new seeps.
' The North Carolina Department of Environment and Natural Resources—Division of Water Resources
(DWR)will be promptly notified if any new seeps are identified or any significant changes are observed
for the existing seeps. If any existing or newly identified seeps are determined to reach Lake Wylie, and
demonstrate reasonable potential to exceed a water quality standard, Duke Energy will do one of the
following: 1)stop the seep, 2)capture and route the seep so that it is discharged through a National
' Pollutant Discharge Elimination System (NPDES) permitted outfall, or 3)address the seep using Best
Management Plans approved by DWR.
' Most of the analytical results upstream and downstream of the ash basin discharge in Lake Wylie with the
exception of copper and zinc are at, or near, the method detection limits and below limits for water quality
standards. Measured values at these two locations are consistent with historical data from previous
' monitoring efforts in Lake Wylie. Duke Energy proposes that the semi-annual in-stream monitoring
frequency be maintained.
' RECEIVED/DENR/DWR
OCT 1 5 Z(114
' Water Qua
Permitting Section
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MINI r r M M NM M a I I =I I E MI - I =
Table 1 —Allen Steam Station Surface Water/Seep Locations and Descriptions
Seep Location Coordinates'
Flow
ID Description2 Seep Description
Latitude Longitude
S-1 35°10.242' 81°0.625' Continuous Located south of Active Ash Basin, north of Nutall Oak Lane. Tributary towards Lake
Wylie.Well-defined stream approximately 3-ft wide.
S-2 35°10.426' 81°0.344' Continuous Located southeast of Active Ash Basin. Tributary towards Lake Wylie.Well-defined
stream approximately 1-ft wide.
S-3 35°10.513' 81°0.360' Continuous Located east of Active Ash Basin.Tributary towards Lake Wylie.Well-defined stream
approximately 2-ft wide.
S-4 35°10.513' 81°0.360' Continuous Located east of Active Ash Basin. Tributary towards Lake Wylie.Well-defined stream
approximately 1.5-ft wide.
S-5 35°10.621' 81°0.366' Continuous Located east of Active Ash Basin. Unconfined diffuse flow towards Lake Wylie.
S-6 35°10.626' 81°0.369' Continuous Located east of Active Ash Basin. Unconfined diffuse flow towards Lake Wylie.
S-7 35°10.664' 81°0.380' Continuous Located east of Active Ash Basin. Unconfined diffuse flow towards Lake Wylie.
S-8 35°10.706' 81°0.391' Continuous Located east of Active Ash Basin. Flow through is concentrated through a 12-inch CMP.
S-9 35°11.146' 81°0.394' Continuous Located east of Active Ash Basin. Flow through is concentrated through a 12-inch CMP.
Notes:
1. Location coordinates(degrees)for seep sampling locations are approximate, and are in NAD 83 datum.
2. Flow description for each seep sample location is based on observation during site visits performed by HDR Engineering, Inc. (HDR)on August
21, 2014. Flow measurements and analytical samples were collected on September 4 and September 9, 2014.
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Table 2—Laboratory Analytical Methods
IParameter Method Reporting Units Laboratory
Limit
i Chemical Oxygen
Demand (COD) HACH 8000 20 mg/L Duke Energy
Chloride(CI) EPA 300.0 1 mg/L Duke Energy
I Fluoride(FI) EPA 300.0 1 mg/L Duke Energy
Sulfate(SO4) EPA 300.0 1 mg/L Duke Energy
I Oil and Grease EPA 1664B 5 ug/L Pace Analytical
Mercury(Hg) EPA 245.1 0.05 ug/L Duke Energy
Aluminum (Al) EPA 200.7 0.005 mg/L Duke Energy
IBarium (Ba) EPA 200.7 0.005 mg/L Duke Energy
Boron (B) EPA 200.7 0.05 mg/L Duke Energy
ICalcium (Ca) EPA 200.7 0.01 mg/L Duke Energy
Hardness EPA 200.7 0.19 mg/L(CaCO3) Duke Energy
IIron (Fe) EPA 200.7 0.01 mg/L Duke Energy
Magnesium (Mg) EPA 200.7 0.005 mg/L Duke Energy
IManganese(Mn) EPA 200.7 0.005 mg/L Duke Energy
Zinc(Zn) EPA 200.7 0.005 mg/L Duke Energy
I Antimony(Sb) EPA 200.8 1 ug/L Duke Energy
Arsenic(As) EPA 200.8 1 ug/L Duke Energy
Cadmium (Cd) EPA 200.8 1 ug/L Duke Energy
IChromium (Cr) EPA 200.8 1 ug/L Duke Energy
Copper(Cu) EPA 200.8 1 mg/L Duke Energy
ILead (Pb) EPA 200.8 1 ug/L Duke Energy
Molybdenum(Mo) EPA 200.8 1 ug/L Duke Energy
INickel (Ni) EPA 200.8 1 ug/L Duke Energy
Selenium (Se) EPA 200.8 1 ug/L Duke Energy
IThallium (TI) Low Level EPA 200.8 0.2 ug/L Duke Energy
TDS SM2540C 25 mg/L Duke Energy
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TSS SM2540D 5 mg/L Duke Energy
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Appendix A
ISeep Flows and Analytical Results
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Appendix A-1

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Parameter Lake Wylie- Lake Wylie-...
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1-9 Upstream43 Downstream '
Oil &Grease r.5 N/A N/A
I COD-Chemical Oxygen Demand 20 N/A N/A
Cl -Chloride(00940) 1.1
N/A N/A
Fl-Fluoride 0.5 N/A N/A
SO4-Sulfate(00945) 80 N/A N/A
1 Hg -Mercury(71900) <1 <1
�1
Al -Aluminum (01105) 254 N/A N/A
IBa-Barium (01007) 029 N/A N/A
B- Boron (01022) .49 N/A N/A
Ca-Calcium 38 N/A N/A
IHardness 113 N/A N/A
Fe- Iron(01045) 942 N/A N/A
' Mg-Magnesium 6.5 N/A N/A
Mn - Manganese(01055) 998 N/A N/A
Zn -Zinc(01092) 283 3.08 <2
I Sb-Antimony(01097) <1 N/A N/A
As-Arsenic(01002) <1 <1 <1
Cd -Cadmium (01027) <1 <1 <1
ICr-Chromium (01034) <1 <1 <1
Cu -Copper(01042) .31 2.80 2.60
I Pb- Lead (01051) <1 <1 <1
Mo-Molybdenum <1
N/A N/A
Ni - Nickel (01067) .78 N/A N/A
I Se-Selenium (01147) <1 <1 <1
TI -Thallium(01059) 0.2
N/A N/A
TDS-Total Dissolved Solids (70300) i00 54 53
ITSS-Total Suspended Solids <5 N/A N/A
pH .52 N/A N/A
Temperature 19 N/A N/A
ISpecific conductance '17 N/A N/A
Flow )002 N/A N/A
I Notes:
1 Flow measurements and analytical sam f
2. N/A indicates not applicable.
III3. Lake Wylie samples were collected on A
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Appendix B
1 Sample Preservation and Hold Times
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Appendix B-1

IParameter Name ' 2,3 Maximum
Container Preservation Holding Time°
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Table IB—inorganic Tests
1.Acidity P, FP, G Cool, 56 °C18 14 days
2. Alkalinity P, FP, G Cool, 56 °C18 14 days
4. Ammonia P, FP, G Cool, 56°C18, H2SO4 to pH <2 28 days
9. Biochemical oxygen demand P, FP, G Cool, 56°C18 48 hours
10. Boron P, FP, or HNO3 to pH <2 6 months
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Quartz
11. Bromide P, FP, G None required 28 days
I 14. Biochemical oxygen demand, P, FP G Cool, 56 °C18 48 hours
carbonaceous
15. Chemical oxygen demand P, FP, G Cool, 56°C18, H2SO4 to pH <2 28 days
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16. Chloride P, FP, G None required 28 days
17. Chlorine,total residual P, G None required Analyze within 15
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minutes
21. Color P, FP, G Cool, 56°C18 48 hours
I 23-24. Cyanide,total or available P, FP, G
(or CATC)and free Cool, 56°C18, NaOH to pH 14 days
>105,6 reducing agent if oxidizer
present
I25. Fluoride P None required 28 days
27. Hardness P, FP, G HNO3 or H2SO4 to pH<2 6 months
I 28. Hydrogen ion (pH) P, FP, G None required Analyze within 15
minutes
31,43. Kjeldahl and organic N P, FP, G Cool, s6°C18, H2SO4 to pH <2 28 days
Table IB—Metals'
18.Chromium VI P, FP, G Cool, s6 °C18, pH =9.3-9.720 28 days
35. Mercury(CVAA) P, FP, G HNO3 to pH <2 28 days
35. Mercury(CVAFS) FP, G;and FP- 5 mUL 12N HCI or 5 mUL 90 daysl7
Ilined capl7 BrCl17
3, 5-8, 12, 13, 19, 20, 22,26,29,30, P, FP, G HNO3 to pH <2, or at least 24 6 months
32-34, 36,37, 45,47, 51, 52, 58-60, hours prior to analysis19
I 62, 63,70-72, 74, 75. Metals,
except boron, chromium VI, and
mercury
I38. Nitrate P, FP, G Cool, s6°C18 48 hours
39. Nitrate-nitrite P, FP, G Cool, 56°C15, H2SO4 to pH <2 28 days
I40. Nitrite P, FP, G Cool, 56°C18 48 hours
41. Oil and grease G Cool to s6°C18, HCI or H2SO4 to 28 days
111pH<2
Appendix B-2

IMaximumParameter Name Container' Preservation2.3
Holding Time'
I 42. Organic Carbon P, FP, G Cool to 56°C18, HCI, H2SO4, or 28 days
H3PO4 to pH <2
44. Orthophosphate P, FP, G Cool, to 56 °C18,24 Filter within 15
I minutes; analyze
within 48 hours
46. Oxygen, Dissolved Probe G, Bottle and None required Analyze within 15
Itop minutes
47.Winkler G, Bottle and Fix on site and store in dark 8 hours
top
1 48. Phenols G Cool, 56°C18, H2SO4 to pH <2 28 days
49. Phosphorous(elemental) G Cool, 56 0C18 48 hours
1 50. Phosphorous,total P, FP, G Cool, 56°C18, H2SO4 to pH <2 28 days
53. Residue, total P, FP, G Cool, 56°C18 7 days
I54. Residue, Filterable P, FP, G Cool, 56 0C18 7 days
55. Residue, Nonfilterable(TSS) P, FP, G Cool, 56 °C18 7 days
I56. Residue, Settleable P, FP, G Cool, 56°C18 48 hours
I 57. Residue, Volatile P, FP, G Cool, 56 °C18 7 days
61. Silica P or Quartz Cool, 56°C18 28 days
I 64. Specific conductance P, FP, G Cool, 56 0C18 28 days
65. Sulfate P, FP, G Cool,
56°C18 28 days
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66. Sulfide P, FP, GCool, 56 °C18, add zinc acetate 7 days
plus sodium hydroxide to pH >9
67. Sulfite P, FP, G None required Analyze within 15
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minutes
68. Surfactants P, FP, G Cool, 56°C18 48 hours
I 69.Temperature P, FP, G None required Analyze
73. Turbidity P, FP, G Cool, 56°C18 48 hours
Notes:
1. "P" is for polyethylene;"FP" is fluoropolymer(polytetrafluoroethylene (PTFE); Teflon®), or other
fluoropolymer, unless stated otherwise in this table; and"G" is glass.
2. Except where noted in this table and the method for the parameter, preserve each grab sample within 15
I minutes of collection. For a composite sample collected with an automated sample(e.g., using a 24-hour
composite sample; see 40 CFR 122.21(g)(7)(i)or 40 CFR Part 403, Appendix E), refrigerate the sample at
56°C during collection unless specified otherwise in this table or in the method(s). For a composite sample
to be split into separate aliquots for preservation and/or analysis, maintain the sample at 56 °C, unless
specified otherwise in this table or in the method(s), until collection, splitting, and preservation is completed.
Add the preservative to the sample container prior to sample collection when the preservative will not
compromise the integrity of a grab sample, a composite sample, or aliquot split from a composite sample
I within 15 minutes of collection. If a composite measurement is required but a composite sample would
compromise sample integrity, individual grab samples must be collected at prescribed time intervals(e.g., 4
samples over the course of a day, at 6-hour intervals). Grab samples must be analyzed separately and the
concentrations averaged. Alternatively, grab samples may be collected in the field and composited in the
I laboratory if the compositing procedure produces results equivalent to results produced by arithmetic
averaging of results of analysis of individual grab samples. For examples of laboratory compositing
Appendix B-3

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procedures, see EPA Method 1664 Rev. A(oil and grease)and the procedures at 40 CFR 141.34(f)(14)(iv)
and (v)(volatile organics).
I 3. When any sample is to be shipped by common carrier or sent via the U.S. Postal Service, it must comply
with the Department of Transportation Hazardous Materials Regulations(49 CFR part 172). The person
offering such material for transportation is responsible for ensuring such compliance. For the preservation
requirement of this table, the Office of Hazardous Materials, Materials Transportation Bureau, Department of
I Transportation has determined that the Hazardous Materials Regulations do not apply to the following
materials: Hydrochloric acid (HCI) in water solutions at concentrations of 0.04% by weight or less (pH about
1.96 or greater; Nitric acid (HNO3) in water solutions at concentrations of 0.15% by weight or less (pH about
1.62 or greater); Sulfuric acid (H2SO4) in water solutions at concentrations of 0.35% by weight or less(pH
about 1.15 or greater); and Sodium hydroxide(NaOH) in water solutions at concentrations of 0.080% by
weight or less(pH about 12.30 or less).
4. Samples should be analyzed as soon as possible after collection. The times listed are the maximum times
I that samples may be held before the start of analysis and still be considered valid. Samples may be held for
longer periods only if the permittee or monitoring laboratory has data on file to show that, for the specific
types of samples under study, the analytes are stable for the longer time, and has received a variance from
1 the Regional Administrator under Sec. 136.3(e). For a grab sample, the holding time begins at the time of
collection. For a composite sample collected with an automated sampler(e.g., using a 24-hour composite
sampler; see 40 CFR 122.21(g)(7)(i)or 40 CFR part 403, Appendix E), the holding time begins at the time of
the end of collection of the composite sample. For a set of grab samples corn posited in the field or
I laboratory, the holding time begins at the time of collection of the last grab sample in the set. Some samples
may not be stable for the maximum time period given in the table. A permittee or monitoring laboratory is
obligated to hold the sample for a shorter time if it knows that a shorter time is necessary to maintain sample
I stability. See 136.3(e)for details. The date and time of collection of an individual grab sample is the date
and time at which the sample is collected. For a set of grab samples to be composited, and that are all
collected on the same calendar date, the date of collection is the date on which the samples are collected.
For a set of grab samples to be composited, and that are collected across two calendar dates, the date of
I collection is the dates of the two days; e.g., November 14-15. For a composite sample collected
automatically on a given date, the date of collection is the date on which the sample is collected. For a
composite sample collected automatically, and that is collected across two calendar dates, the date of
I collection is the dates of the two days; e.g., November 14-15. For static-renewal toxicity tests, each grab or
composite sample may also be used to prepare test solutions for renewal at 24 h, 48 h, and/or 72 h after
first use, if stored at 0-6 °C, with minimum head space.
IS. ASTM D7365-09a specifies treatment options for samples containing oxidants (e.g., chlorine). Also, Section
9060A of Standard Methods for the Examination of Water and Wastewater(20th and 21st editions)
addresses dechlorination procedures.
6. Sampling, preservation and mitigating interferences in water samples for analysis of cyanide are described
I in ASTM D7365-09a. There may be interferences that are not mitigated by the analytical test methods or
D7365-09a.Any technique for removal or suppression of interference may be employed, provided the
laboratory demonstrates that it more accurately measures cyanide through quality control measures
I described in the analytical test method. Any removal or suppression technique not described in D7365-09a
or the analytical test method must be documented along with supporting data.
7. For dissolved metals, filter grab samples within 15 minutes of collection and before adding preservatives.
For a composite sample collected with an automated sampler(e.g., using a 24-hour composite sampler; see
I 40 CFR 122.21(g)(7)(i)or 40 CFR Part 403, Appendix E),filter the sample within 15 minutes after
completion of collection and before adding preservatives. If it is known or suspected that dissolved sample
integrity will be compromised during collection of a composite sample collected automatically over time
I (e.g., by interchange of a metal between dissolved and suspended forms), collect and filter grab samples to
be composited (footnote 2) in place of a composite sample collected automatically.
8. Guidance applies to samples to be analyzed by GC, LC, or GC/MS for specific compounds.
I 9. If the sample is not adjusted to pH 2, then the sample must be analyzed within seven days of sampling.
10. The pH adjustment is not required if acrolein will not be measured. Samples for acrolein receiving no pH
adjustment must be analyzed within 3 days of sampling.
I11. When the extractable analytes of concern fall within a single chemical category, the specified preservative
and maximum holding times should be observed for optimum safeguard of sample integrity(i.e., use all
necessary preservatives and hold for the shortest time listed).When the analytes of concern fall within two
or more chemical categories, the sample may be preserved by cooling to 56 °C, reducing residual chlorine
I with 0.008%sodium thiosulfate, storing in the dark, and adjusting the pH to 6-9; samples preserved in this
manner may be held for seven days before extraction and for forty days after extraction. Exceptions to this
optional preservation and holding time procedure are noted in footnote 5(regarding the requirement for
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Appendix B-4

' thiosulfate reduction), and footnotes 12, 13(regarding the analysis of benzidine).
12. If 1,2-diphenylhydrazine is likely to be present, adjust the pH of the sample to 4.0±0.2 to prevent
' rearrangement to benzidine.
13. Extracts may be stored up to 30 days at<0 °C.
14. For the analysis of diphenylnitrosamine, add 0.008% Na2S2O3 and adjust pH to 7-10 with NaOH within 24
' hours of sampling.
15. The pH adjustment may be performed upon receipt at the laboratory and may be omitted if the samples are
extracted within 72 hours of collection. For the analysis of aldrin, add 0.008% Na2S2O3.
16. Place sufficient ice with the samples in the shipping container to ensure that ice is still present when the
' samples arrive at the laboratory. However, even if ice is present when the samples arrive, immediately
measure the temperature of the samples and confirm that the preservation temperature maximum has not
been exceeded. In the isolated cases where it can be documented that this holding temperature cannot be
' met, the permittee can be given the option of on-site testing or can request a variance.The request for a
variance should include supportive data which show that the toxicity of the effluent samples is not reduced
because of the increased holding temperature. Aqueous samples must not be frozen. Hand-delivered
samples used on the day of collection do not need to be cooled to 0 to 6 °C prior to test initiation.
' 17. Samples collected for the determination of trace level mercury(<100 ng/L)using EPA Method 1631 must be
collected in tightly-capped fluoropolymer or glass bottles and preserved with BrCI or HCI solution within 48
hours of sample collection. The time to preservation may be extended to 28 days if a sample is oxidized in
' the sample bottle. A sample collected for dissolved trace level mercury should be filtered in the laboratory
within 24 hours of the time of collection. However, if circumstances preclude overnight shipment, the sample
should be filtered in a designated clean area in the field in accordance with procedures given in Method
1669. If sample integrity will not be maintained by shipment to and filtration in the laboratory, the sample
must be filtered in a designated clean area in the field within the time period necessary to maintain sample
integrity. A sample that has been collected for determination of total or dissolved trace level mercury must
be analyzed within 90 days of sample collection.
' 18. Aqueous samples must be preserved at 56°C, and should not be frozen unless data demonstrating that
sample freezing does not adversely impact sample integrity is maintained on file and accepted as valid by
the regulatory authority. Also, for purposes of NPDES monitoring, the specification of"5°C" is used in place
' of the"4°C" and "<4 °C" sample temperature requirements listed in some methods. It is not necessary to
measure the sample temperature to three significant figures(1/100th of 1 degree); rather, three significant
figures are specified so that rounding down to 6 °C may not be used to meet the 56°C requirement.The
preservation temperature does not apply to samples that are analyzed immediately(less than 15 minutes).
19. An aqueous sample may be collected and shipped without acid preservation. However, acid must be added
at least 24 hours before analysis to dissolve any metals that adsorb to the container walls. If the sample
must be analyzed within 24 hours of collection, add the acid immediately(see footnote 2). Soil and sediment
' samples do not need to be preserved with acid. The allowances in this footnote supersede the preservation
and holding time requirements in the approved metals methods.
20. To achieve the 28-day holding time, use the ammonium sulfate buffer solution specified in EPA Method
218.6.The allowance in this footnote supersedes preservation and holding time requirements in the
approved hexavalent chromium methods, unless this supersession would compromise the measurement, in
which case requirements in the method must be followed.
21. Holding time is calculated from time of sample collection to elution for samples shipped to the laboratory in
' bulk and calculated from the time of sample filtration to elution for samples filtered in the field.
22. Sample analysis should begin as soon as possible after receipt; sample incubation must be started no later
than 8 hours from time of collection.
' 23. For fecal coliform samples for sewage sludge(biosolids)only, the holding time is extended to 24 hours for
the following sample types using either EPA Method 1680(LTB-EC)or 1681 (A-1): Class A composted,
Class B aerobically digested, and Class B anaerobically digested.
' 24. The immediate filtration requirement in orthophosphate measurement is to assess the dissolved or bio-
available form of orthophosphorus(i.e., that which passes through a 0.45-micron filter), hence the
requirement to filter the sample immediately upon collection (i.e., within 15 minutes of collection). [38 FR
28758, Oct. 16, 1973].
Appendix B-5

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LEGEND:
DUKE ENERGY PROPERTY BOUNDARY
----
ASH BASIN WASTE BOUNDARY
ASH STORAGE AREA BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
_ -
ASH BASIN COMPLIANCE BOUNDARY
COINCIDENT WITH DUKE PROPERTY BOUNDARY
- -
STREAM
TOPOGRAPHIC CONTOUR 14-FT INTERVAL)
ASH BASIN COMPLIANCE GROUNDWATER
MONITORING WELL
SEEP SAMPLE LOCATION
Ak
NPDES OUTFALL LOCATION
NOTES: =R QUALITY
1. PARCEL DATA FOR THE SITE WAS OBTAINED FROM DUKE ENERGY
2. WASTE BOUNDARY IS APPROXIMATE.
3. AS -BUILT MONITORING WELL LOCATIONS PROVIDED BY DUKE ENP
4. TOPOGRAPHY DATA FOR THE SITE WAS OBTAINED FROM NC DC
5. AERIAL PHOTOGRAPHY WAS OBTAINED FROM WSP DATED APRIL SI N
6. THE COMPLIANCE BOUNDARY IS ESTABLISHED ACCORDING TO TDLINA
7. SEEP SAMPLING LOCATIONS ARE APPROXIMATE.
8. NPDES OUTFALL LOCATIONS PROVIDED BY DUKE ENERGY.
DATE
SEPTEMBER 30, 2014
FIGURE
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