NC0004987_Seep Monitoring Information 2014_20141015

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Seep Monitoring InformationIP
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Marshall Steam
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Station
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1 August and September 2014
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1 RECEIVEDIDENRIDWR
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Water QSeon
ty
1 Permitting

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1 Marshall Steam Station
Surface Water and Seep Monitoring
1 August and September 2014
Introduction
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Flow and water quality measurements were collected at one seep sampling location(S-1)and two
locations near the ash basin (Lake Norman-Upstream and Lake Norman-Downstream)associated with
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Duke Energy's Marhsall Steam Station, located in Catawba County, North Carolina. The purpose of the
sampling, which was conducted in September 2014, was to measure seepage flows and provide sufficient
depth to allow collection of water quality samples for laboratory analysis. Seep location S-2 was not
I sampled due to an absence of flow during this monitoring event. 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.
ISeep Flow Measurement Method and Results
I A V-notch weir apparatus was utilized at location S-1 to impound the seepage in a channel, which
concentrated discharge to a central location that allowed for a flow measurement to be obtained. The
weir was constructed from '4-inch-thick Plexiglas board material.The device was inspected after
I 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.
The seepage flows at location S-1 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
I mL)were measured in the field utilizing a graduated container.The amount of time(in 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
I Water quality samples were collected at S-1. To minimize potential effects of stormwater runoff, seep
samples were collected during a period with minimal preceding rainfall. Samples were collected from the
discharge flow at the flow measurement device described above or directly from the seep into sample
Ibottles while minimizing disturbance and entrainment of soil/sediment.
Analytical parameters for analysis were: TSS, TDS, Oil &Grease, CI, SO4, F, COD, Al, As, B, Ba, Ca, Cd,
Cu, Cr, Fe, Mn, Mo, Mg, Ni, Pb, Sb, Se,TI, Zn, Hardness, and Hg. Storage and preservation techniques
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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
Ifor each parameter are provided in Table 2 and analytical results are presented in Appendix A.
Seep In-situ Measurement Method and Results
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In-situ field parameters (temperature, pH, and specific conductance)were measured at location S-1
utilizing calibrated field meters either at the discharge of the seep directly, at the discharge of the flow
I 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.
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Lake Norman Water Quality and In-situ Sample Collection Method and Results
IWater quality samples and in-situ measurements from the Lake Norman were collected at a location
upstream (Lake Norman-Upstream) and downstream (Lake Norman-Downstream)of Marshall Steam
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Station (Figure 2). Additionally, water samples and in-situ measurements were collected from an in-
process ash basin location (Figure 1).The grab samples were collected from the river and basin's surface
(0.3 m)directly into appropriate sample bottles. Preservation and analyses methods for the river and ash
basin samples are provided in Table 2 and Appendix B.
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All trace metal results were low, with most values either tabulated as less than the analytical reporting
limit(RL)for the method or close to the RL(Table 1). For examples, all samples for arsenic, cadmium.
I Mercury, lead and selenium were report as less that the RL, whereas only four zinc values were greater
than the RL of 1.0 pg/L.All zinc values were below the water quality standard (50 pg/L). Most of the
copper values were above the RL, but onle marginally so, all values were also well below the water
I quality standard (7.0 pg/L).Total dissolved solids (TDS)values were low, and reflective of the low ionic
strength and conductivity of waters in Lake Norman and the Catawba River Basin. All values for the nine
water quality parameters monitored below NC water quality standards. Duke energy proposes that the in-
Istream monitoring frequency be reduced for semi-annually to annually.
Recommendations
IThe 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 Marshall Steam Station to influence water quality in
I the Lake Norman. 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
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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
I (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 the Lake Norman,
and demonstrate reasonable potential to exceed a water quality standard, Duke Energy will do one of the
1 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.
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' NOTES:
1. PARCEL DATA FOR THE SITE WAS OBTAINED FROM DUKE ENERGY REAL ESTATE AND IS APPROXIMATE.
2. WASTE BOUNDARY AND ASH STORAGE AREA BOUNDARY ARE APPROXIMATE.
3. AS -BUILT MONITORING WELL LOCATIONS PROVIDED BY DUKE ENERGY.
4. COMPLIANCE SHALLOW MONITORING WELLS (5) ARE SCREENED ACROSS THE SURFICIAL WATER TABLE.
' 5. COMPLIANCE DEEP MONITORING WELLS (D) ARE SCREENED IN THE TRANSITION ZONE BETWEEN COMPETENT BEDROCK AND THE REGOLITH.
6. TOPOGRAPHY DATA FOR THE SITE WAS OBTAINED FROM NC DOT GEOGRAPHIC INFORMATION SYSTEM (GIS) WEB SITE (DATED 2007).
7. AERIAL PHOTOGRAPHY WAS OBTAINED FROM WSP DATED APRIL 2014.
8. THE COMPLIANCE BOUNDARY IS ESTABLISHED ACCORDING TO THE DEFINITION FOUND IN 15A NCAC 02L.0107 (a).
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SCALE (FEET)
5000 500 1.000
r 1. ono'
F�2
IDENTIFIED SEEPS AND WATER QUALITY
SAMPLE LOCATION MAP
DUKE ENERGY CAROLINAS, LLC
MARSHALL STEAM STATION ASH BASIN
CATAWBA COUNTY, NORTH CAROLINA
NPDES PERMIT #NC0004987
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LEGEND:
DUKE ENERGY PROPERTY BOUNDARY
ASH BASIN WASTE BOUNDARY
LANDFILL/STRUCTURAL FILL BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY COINCIDENT
WITH DUKE PROPERTY BOUNDARY
STREAM
TOPOGRAPHIC CONTOUR )4-FT INTERVAL)
ASH BASIN COMPLIANCE GROUNDWATER
�I MONITORING WELL
• SEEP SAMPLE LOCATION
. NPDES OUTFALL LOCATION
DATE
SEPTEMBER 30, 2014
FIGURE
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/ . r �✓ _ I�j 4/ 15.9 (Upstream)
Ash Basin {a
Ram
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�• E • cam„c ' t..
Steam Station
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14.0 (Downstream)' - d
Surface Water Sampling Locations
, 1b ` /� :� / Note
1. Surface water sample locations provided by
Duke Energy Carolinas. LLC.
2. USGS. 1993. Lake Norman 24K Quad.
SCALE (FEET)
tt�; 1. Q" Feet
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p,r-, Co 0 1.000 2.000 4.000
DATE
SURFACE WATER QUALITY SAMPLE LOCATION October 1, 2014
MARSHALL STEAM STATION
DUKE ENERGY CAROLINAS, LLC FIGURE
rtoa e�9�o.•�„y. m�
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M : CATAWBA COUNTY, NORTH CAROLINA L'

I r En MG NM 1 IN r i — NE MN R MI MI MN — MI NE
Table 1 —Marshall Steam Station Surface Water/Seep Locations and Descriptions
Seep Location Coordinates'
Flow
ID Description2 Seep Description
Latitude Longitude
S-1 35°36.712' 80°57.621' Continuous Located northeast of Active Ash Basin.Tributary toward Lake Norman.Well-defined
stream approximately 2.5-ft wide.
S-2 35°42.560' 80°21.566' No Flow Located east of Active Ash Basin. Sheet flow toward Lake Norman. No visible flow was
evident during the site visit.
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
26, 2014. Flow measurements and analytical samples were collected on September 4, 2014.
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I Table 2—Laboratory Analytical Methods
Parameter 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
IFluoride(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
I Aluminum (Al) EPA 200.7 0.005 mg/L
mg/L Duke Energy
Barium (Ba) EPA 200.7 0.005 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
IAntimony(Sb) EPA 200.8 1 ug/L Duke Energy
Arsenic(As) EPA 200.8 1 ug/L Duke Energy
I Cadmium (Cd) EPA 200.8 1 ug/L Duke Energy
Chromium (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
ITSS SM2540D 5 mg/L Duke Energy
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Appendix A
ISeep Flows and Analytical Results
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IAppendix A-1

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Marshall Steam Station
Surface Water/Seep Monitoring Analytical Results—August 2013 and September 2014
Seep Monitoring Location''2 Lake Norman Lake Norman
Parameter Units 34 34
S-1 S-2 15.9 Upstream ' 14.0 Downstream
Oil &Grease mg/I <5 — N/A N/A
COD-Chemical Oxygen Demand mg/I <20 — N/A N/A
CI-Chloride(00940) mg/I 5.1 — N/A N/A
Fl - Fluoride mg/I <0.5 — N/A N/A
SO4-Sulfate(00945) mg/I 290 — N/A N/A
Hg -Mercury(71900) Ng/I <0.05 — <0.05 <0.05
Al -Aluminum (01105) mg/I 0.278 — N/A N/A
Ba- Barium (01007) mg/I 0.098 -- N/A N/A
B-Boron (01022) mg/I <3.99 — N/A N/A
Ca-Calcium mg/I 63.3 -- N/A N/A
Hardness mg/I (CaCO3) 291 — N/A N/A
Fe- Iron (01045) mg/I 4.41 -- N/A N/A
Mg-Magnesium mg/I 32.3 -- N/A N/A
Mn -Manganese(01055) mg/I 0.936 — N/A N/A
Zn -Zinc(01092) mg/I <0.005 — <1 2.23
Sb-Antimony(01097) Ng/I <1 -- N/A N/A
As -Arsenic(01002) Ng/I <1 -- <1 <1
Cd -Cadmium (01027) Ng/I <1 -- <1 <1
Cr-Chromium (01034) Ng/I <1.47 -- <1 <1
Cu - Copper(01042) Ng/I 1 -- 2.46 5.06
Pb- Lead (01051) Mil <1 — <1 <1
Mo-Molybdenum Ng/I <1 -- N/A N/A
Ni - Nickel (01067) Ng/I <1.93 — N/A N/A
Se-Selenium (01147) Ng/I <4.58 -- <1 <1
TI-Thallium (01059) Ng/I <0.2 — N/A N/A
TDS -Total Dissolved Solids (70300) mg/I 530 -- 40 60
TSS-Total Suspended Solids mg/I 18 -- N/A N/A
pH s.u. 6.55 -- N/A N/A
Temperature °C 21.5 -- N/A N/A
Specific conductance NS/cm 2700 — N/A N/A
Flow MGD 0.0019 — N/A N/A
Notes.
1.Flow measurements at S1 was collected on September 4,2014. 3.Lake Norman Samples were collect on August 5,2013.
2.Seep S2 was not sampled due to absence of flow during this monitoring event. 4.N/A indicates not applicable
Appendix A-2

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Appendix B
ISample Preservation and Hold Times
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IAppendix B-1

IMaximum
Parameter Name Container' Preservation2,3 a
Holding Time
Table IB—Inorganic Tests
1. Acidity P, FP, G Cool, 56 °C18 14 days
2.Alkalinity P, FP, G Cool, 56°C'" 14 days
4.Ammonia P, FP, G Cool, 56 °Cm, H2SO4 to pH <2 28 days
I9. 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°C16 48 hours
carbonaceous
15. Chemical oxygen demand P, FP, G Cool, 56°C16, H2SO4 to pH <2 28 days
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, s6 °C16 48 hours
I 23-24. Cyanide,total or available P, FP, G
(or CATC)and free Cool, 56 °C16, 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, 56 °C18, H2SO4 to pH <2 28 days
Table IB—Metals
18. Chromium VI P, FP, G Cool, 56 °C16, 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 cap17 BrCI"
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
' 62, 63, 70-72, 74, 75. Metals,
except boron, chromium VI, and
mercury
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38. Nitrate P, FP, G Cool, 56 °C16 48 hours
39. Nitrate-nitrite P, FP, G Cool, 56 °C76, H2SO4 to pH <2 28 days
' 40. Nitrite P, FP, G Cool, 56°C16 48 hours
41. Oil and grease G Cool to 56 °C16, HCI or H2SO4 to 28 days
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pH <2
IAppendix B-2

2,3 Maximum
Parameter Name Container Preservation Holding Time4
I 42. Organic Carbon P, FP, G Cool to 56
°C18, HCI, H2SO4, or 28 days
H3PO4 to pH <2
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44. Orthophosphate P, FP, G Cool, to 56 °C18,24 Filter within 15
minutes; analyze
within 48 hours
I 46. Oxygen, Dissolved Probe G, Bottle and None required
top Analyze within 15
minutes
47.Winkler G, Bottle and Fix on site and store in dark 8 hours
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top
48. Phenols G Cool, 56°C'8, H2SO4 to pH<2 28 days
I 49. Phosphorous (elemental) G Cool, s6 °C'� 48 hours
50. Phosphorous,total P, FP, G Cool, 56°C18, H2SO4 to pH <2 28 days
I 53. Residue,total P, FP, G Cool, 56 °C'" 7 days
54. Residue, Filterable P, FP, G Cool, 56 .0 7 days
I 55. Residue, Nonfilterable(TSS) P, FP, GCool, s6 °C'" 7 days
56. Residue, Settleable P, FP, G Cool, 5
6 00 48 hours
I57. Residue,Volatile P, FP, G Cool, 56 °C18 7 days
61. Silica P or Quartz Cool, 56°C18 28 days
I64. Specific conductance P, FP, G Cool, 56°0 28 days
65. Sulfate P, FP, G Cool, 56°C'" 28 days
I 66. Sulfide P, FP, G Cool, 56 °Cm, 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 acts 48 hours
I69.Temperature P, FP, G None required Analyze
73.Turbidity P, FP, G Cool, 56 °Cm 48 hours
I 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
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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
I 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
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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
I concentrations averaged. Alternatively, grab samples may be collected in the field and composited in the
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
IAppendix B-3

Iprocedures, 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
ITransportation 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
I 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).
I 4. Samples should be analyzed as soon as possible after collection. The times listed are the maximum times
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
I 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
I the end of collection of the composite sample. For a set of grab samples composited in the field or
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.
I For a set of grab samples to be composited, and that are collected across two calendar dates, the date of
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.
I 5. 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.
I 11. 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 s6 °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
IAppendix 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
I 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
I 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.
I 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
I 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
I 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
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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
I 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.
I 18. Aqueous samples must be preserved at s6 °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"s°C" is used in place
I 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 s6 °C requirement. The
preservation temperature does not apply to samples that are analyzed immediately(less than 15 minutes).
I 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
I 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
I 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
I 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.
I 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.
I 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].
I
I
IAppendix B-5