#248_2022_0718_MC_Revised_FINAL

On-Site Inspection Report

LABORATORY NAME: Duke Power Company LLC d/b/a Duke Energy Carolinas LLC
NPDES PERMIT #:
NC0001422, NC0003417, NC0003425, NC0003433,
NC0003468, NC0004774, NC0004979, NC0004987,
NC0005088, NC0005363, NC0024392, NC0024406,
NC0038377, NC0039586
ADDRESS: 13339 Hagers Ferry Road
Huntersville, NC 28078-7929
CERTIFICATE #: 248
DATE OF INSPECTION: July 18, 2022
TYPE OF INSPECTION: Industrial Maintenance
AUDITOR(S): Michael Cumbus, Jill Puff, Tonja Springer and Beth Swanson

LOCAL PERSON(S) CONTACTED:

Girish Sharma, Garrett Hutchings, Chad Spence, Maggie Hall,
Jesse Arias, Bonnie Young, Dale Mace and Johnny Haynes

I. INTRODUCTION:

This laboratory was inspected by a representative of the North Carolina Wastewater/Groundwater Laboratory
Certification Branch (NC WW/GW LCB) to verify its compliance with the requirements of 15A NCAC 02H
.0800 for the analysis of compliance monitoring samples.

II. GENERAL COMMENTS:

The facility is neat, well maintained and well organized and has all the equipment necessary to perform
the analyses. Staff were very knowledgeable, forthcoming and responded well to suggestions from the
auditors.

All required Proficiency Testing (PT) Samples have been analyzed and the laboratory has fulfilled its PT
requirements for the 2022 PT Calendar Year.

The laboratory is reminded that any time changes are made to laboratory procedures, QA/SOP
document(s) must be updated and relevant staff retrained. Staff must acknowledge that they have read
and understand the changes as part of the documented training program. The same requirements apply
when changes are made in response to Findings, Recommendations or Comments listed in this report, to
ensure the methods are being performed as stated, references to methods are accurate, and the QA
and/or SOP document(s) is in agreement with each approved practice, test, analysis, measurement,
monitoring procedure or regulatory requirement being used in the laboratory. In some instances, the
laboratory may need to create an SOP to document how new functions or policies will be implemented.
Revisions to the SOPs, based on the Findings, Comments and Recommendations within this
report must be submitted to this office by November 30, 2023.

The laboratory is also reminded that SOPs are required to be reviewed at least every two years and are
intended to describe procedures exactly as they are to be performed. Use of the word “should” is not
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appropriate when describing requirements (e.g., Quality Control (QC) frequency, acceptance criteria, etc.).
Evaluate all SOPs for the proper use of the word “should”.

Laboratory Fortified Matrix (LFM) and Laboratory Fortified Matrix Duplicate (LFMD) are also known as
Matrix Spike (MS) and Matrix Spike Duplicate (MSD) and may be used interchangeably in this report.
Laboratory Fortified Blank (LFB) is also known as Laboratory Control Standard (LCS) and may be used
interchangeably in this report.

Contracted analyses are performed by Pace Analytical Services LLC – West Columbia (Certification #329),
Pace Analytical Services LLC – Huntersville (Certification #12), Pace Analytical Services LLC – Asheville
(Certification #40), and GEL Laboratories LLC (Certification #233).

At the time of the inspection, the following parameters were being subcontracted to other laboratories for
compliance sample analyses: Phosphorus, Turbidity, Ammonia-Nitrogen, Nitrate + Nitrite Nitrogen, Total
Kjeldahl Nitrogen (TKN) and Alkalinity.

III. FINDINGS, REQUIREMENTS, COMMENTS AND RECOMMENDATIONS:

Documentation

Comment: The laboratory recently acquired a second instrument for Mercury analysis. The analyst
commented that they anticipate separating Methods EPA 245.1 and SW-846 7470A and eliminate
combined runs. The instrument identification is located on the initial page of the raw data package as
part of the data software. However, the data package cover sheets, QC batch reports and instrument
run logs list only the model number of the instrument. The laboratory must update all associated
paperwork to ensure that traceable links include the correct instrument.

A. Finding: Error corrections are not always properly performed.

Requirement: All documentation errors shall be corrected by drawing a single line through
the error so that the original entry remains legible. Entries shall not be obliterated by erasures
or markings. Wite-Out®, correction tape, or similar products designed to obliterate
documentation shall not to be used; instead, the correction shall be written adjacent to the
error. The correction shall be initialed by the responsible individual and the date of change
documented. Ref: 15A NCAC 02H .0805 (a) (7) (E).

Comment: Several instances were noted where changes were written over the initial data.
(e.g., The temperature reading for the Metals Hot Block #22 on June 9, 2022 was written over,
and lacked a date of change and the analyst’s initials.

B. Finding: Documentation for the Standard Preparation Logs for metals standards is
sometimes lacking pertinent information: the final concentration of the prepared solutions.

Requirement: All analytical records, including original observations and information
necessary to facilitate historical reconstruction of the calculated results, shall be maintained
for five years. All analytical data and records pertinent to each certified analysis shall be
available for inspection upon request. Ref: 15A NCAC 02H .0805 (a) (7) (E).

Comment: The Standard Preparation Log for the Reporting Limit Standard (RLS) for
Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) analyses lacks the
final concentration for individual analytes.

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C. Finding: Some benchsheets do not fully reference the approved methods.

Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall
be traceable to the associated sample analyses and shall consist of: the method or Standard
Operating Procedure. Each item shall be recorded each time samples are analyzed. Ref: 15A
NCAC 02H .0805 (a) (7) (F) (i).

Comment: The QC Batch reports and Water Quality Data benchsheets for Total Suspended
Residue (TSR) and Total Dissolved Residue (TDR) are missing the method year.

Comment: The analytical benchsheet, QC Batch reports and Water Quality Data
benchsheets for pH are missing the method year.

Comment: The Order Summary Report lacks revision numbers for EPA Methods and the
method year for Standard Methods analyses.

D. Finding: The preparation of standards and use of reagents and consumables are not always
documented in such a way as to provide traceability from preparation to analysis.

Requirement: Chemical containers shall be dated when received and when opened.
Reagent containers shall be dated, identified, and initialed when prepared. Chemicals and
reagents exceeding the expiration date shall not be used. The laboratory shall have a
documented system of traceability for the purchase, preparation, and use of all chemicals,
reagents, standards, and consumables. Ref: 15A NCAC 02H .0805 (a) (7) (K).

Requirement: 15A NCAC 02H .0805 (a) (7) (K) and (g) (7) requires laboratories to have a
documented system of traceability for the purchase, preparation, and use of all chemicals,
reagents, standards, and consumables. That system must include documentation of the
following information: Date received, Date Opened (in use), Vendor, Lot Number, and
Expiration Date (where specified). A system (e.g., traceable identifiers) must be in place that
links standard/reagent preparation information to analytical batches in which the solutions are
used. Documentation of solution preparation must include the analyst’s initials, date of
preparation, the volume or weight of standard(s) used, the solvent and final volume of the
solution. This information as well as the vendor and/or manufacturer, lot number, and
expiration date must be retained for primary standards, chemicals, reagents, and materials
used for a period of five years. Consumable materials such as pH buffers, lots of pre-made
standards and/or media, solids and bacteria filters, etc. are included in this requirement. Ref:
NC WW/GW LCB Traceability Documentation Requirements for Chemicals, Reagents,
Standards and Consumables Policy.

Comment: The laboratory retains Certificates of Analysis (COA) for purchased metals stock
solutions in the receiving department. These are labeled with a unique tracking number and
include a space for the Date Opened. However, that location is not utilized and the Date
Opened is only recorded on the bottle. While this can provide a traceability link to analyses
while the chemicals are still in use, that link is lost once the bottles are discarded.

Comment: The laboratory is lacking documentation for the lot numbers of the Stable-Weigh
bags used in residue analyses.

Comment: There was no documentation of the preparation of the working Internal Standard
(IS) solution or the Spectral Interference Check (SIC) working solution for samples analyzed
by ICP-OES.

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Comment: The laboratory benchsheets for Mercury analysis and metals analyses by
Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) and ICP-OES do not document
the lot numbers of the spiking solutions used to prepare the LFB or LFM/LFMD.

Comment: Preparation of the MS and MSD samples for Total Kjeldahl Nitrogen (TKN), Nitrate
+ Nitrite (NO2+NO3) Nitrogen, Ammonia Nitrogen and Total Organic Carbon (TOC) is not
being documented.

E. Finding: The laboratory benchsheet is lacking required documentation: units of measure.

Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall
be traceable to the associated sample analyses and shall consist of: the proper units of
measure. Each item shall be recorded each time that samples are analyzed. Ref: 15A NCAC
02H .0805 (a) (7) (F) (xii).

Comment: The QC Batch sheets for metals analyses record the volume of spiking solution
added to the sample but lack the units of measure for the spiking solution.

F. Finding: The laboratory benchsheet for ICP-OES is lacking required documentation: the
spectral wavelength used to report results.

Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall
be traceable to the associated sample analyses and shall consist of: any other data needed
to reconstruct the final calculated result. Each item shall be recorded each time that samples
are analyzed. Ref: 15A NCAC 02H .0805 (a) (7) (F) (xviii).

Requirement: Detection limits and linear ranges for the elements will vary with the
wavelength selected, the spectrometer, and the matrices. Table 1 provides estimated
instrument detection limits for the listed wavelengths.7 However, actual method detection
limits and linear working ranges will be dependent on the sample matrix, instrumentation,
and selected operating conditions. Ref: EPA Method 200.7, Rev. 4.4 (1994), Section 1.10.

Requirement: The wavelengths listed are recommended because of their sensitivity and
overall acceptability. Other wavelengths may be substituted if they can provide the needed
sensitivity and are treated with the same corrective techniques for spectral interference
(see Section 4.1). Ref: EPA Method 200.7, Rev. 4.4 (1994); Table I, Footnote a.

Comment: The laboratory currently calibrates and monitors multiple wavelengths for a
number of elements. However, there is no documentation to show which wavelength is
used to report data. Additionally, there is no indication as to why a particular wavelength is
selected, and reporting limits in the SOP are only established for the primary wavelength.

G. Finding: The laboratory benchsheet is lacking required documentation: acceptance criteria
for the analytical balance verification checks.

Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall
be traceable to the associated sample analyses and shall consist of: all quality control
assessments. Each item shall be recorded each time that samples are analyzed. Ref: 15A
NCAC 02H .0805 (a) (7) (F) (xv).

Comment: This Finding applies to Oil & Grease samples analyzed by EPA Method 1664,
Rev. B.

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H. Finding: The laboratory MDL spreadsheet is lacking required documentation: instrument
identification.

Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall
be traceable to the associated sample analyses and shall consist of: the instrument
identification. Ref: 15A NCAC 02H .0805 (a) (7) (F) (iii).

Comment: The laboratory SOP “Determination of the Method Detection Limit” (document #:
ADMP-ENV-ENS-00128) states in Section 9.2.1.1 “If there are multiple instruments that will
be assigned the same MDL, then the sample analyses must be distributed across all of the
instruments.” Further, Section 9.2.1.2 states “A minimum of two spiked samples and two
method blank samples prepared and analyzed on different calendar dates are required for
each instrument.” However, the spreadsheet provided in the SOP only contains a space for
the instrument identification in the Header, and not with each replicate. Please submit an
updated MDL spreadsheet with data with your Response.

Comment: The laboratory currently has two instruments for ICP-MS, two instruments for
anions and two for Mercury analyses.

General

Comment: The term “batches” is not consistently defined or applied from parameter to parameter.
Some parameters (e.g. Mercury) have only an analytical batch and not a preparation batch. Some
parameters (e.g. ICP-OES) define a Preparation Batch and Analytical Batch by job number. While no
instances were noted where QC was lacking due to variances in batch size, this can make review by
outside parties difficult if laboratory personnel are not present to answer questions.

Recommendation: It is recommended that during the next round of SOP revisions, the laboratory
replace references and examples of handwritten and manually entered data, with discussion of
uploading data electronically to the LIMS or server.

Quality Assurance / Quality Control (QA/QC)

I. Finding: The Reference Temperature-Measuring Device (TMD) calibration has expired.

Requirement: A Reference Temperature-Measuring Device is an NIST traceable
temperature-measuring device used only to verify the calibration of other temperature-
measuring devices (i.e., limited use only). This device must be able to distinguish
temperature changes of 0.1°C and equilibrate rapidly. It must be recalibrated in accordance
with the manufacturer’s recalibration date (not to exceed five years). If no recalibration date
is given, the Reference Temperature-Measuring Device must be recalibrated, at a
minimum, every five years. A new certificate of traceability must be issued and maintained
for inspection upon request. Recalibrate sooner if the device has been exposed to
temperatures beyond the manufacturer’s recommended range of use. Ref: NC WW/GW
LCB Temperature-Measuring Devices used for Laboratory Operations Policy.

Comment: The calibration certificate for the Reference TMD (serial number
ELCHM31663), performed by Trescal on January 18, 2018 expired on January 31, 2019
as stated on the certificate. NC WW/GW LCB Temperature-Measuring Devices used for
Laboratory Operations Policy states: “Temperature-measuring device calibrations are
performed by NIST, the manufacturer or any International Organization for Standardization
(ISO) 17025 compliant vendor and results in the issuance of a new certificate of traceability
to NIST standards.” It is recommended that the laboratory inquire whether a longer
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expiration date, up to five years, can be included on the vendor's calibration certificate.
Please include a copy of the new calibration certificate with your Response.

J. Finding: Laboratory temperature-measuring devices are not replaced if the reading is >1
°C different from the Reference Temperature-Measuring Device.

Requirement: Digital temperature-measuring devices not used in an incubator must verify
within 1.0 °C of a Reference Temperature-Measuring Device with a stated accuracy of at
least ± 0.5 °C. These devices must be able to distinguish temperature changes of 1.0 °C
and equilibrate rapidly. If the temperature-measuring device reading differs from the
Reference Temperature-Measuring Device by ≤ 1.0 °C during subsequent verifications, a
correction factor must be applied. If the reading differs by > 1.0 °C, the temperature-
measuring device must be replaced. Ref: NC WW/GW LCB Temperature-Measuring
Devices used for Laboratory Operations Policy.

Comment: The laboratory submitted the verification for the TDR oven. The laboratory
needs to review the Policy and ensure that the 1.0 °C requirement is being applied to all
temperature-measuring devices used for laboratory operations.

K. Finding: Thermometers in the TSR and TDR ovens are not being verified at the
appropriate frequency.

Requirement: Digital temperature-measuring devices and temperature-measuring
devices used in incubators shall be verified at the temperature of use every three months
against a Reference Temperature-Measuring Device and their accuracy shall be corrected.
Ref: 15A NCAC 02H .0805 (a) (7) (N) (iii).

Comment: The digital TMD on the ovens for TDR and TSR are being verified annually.

L. Finding: The laboratory is not evaluating the recovery of the SIC.

Requirement: Each laboratory shall develop documentation outlining the analytical quality
control practices used for the Parameter Methods included in its Certification, including
Standard Operating Procedures for each certified Parameter Method. Quality assurance,
quality control, and Standard Operating Procedure documentation shall indicate the effective
date of the document and be reviewed every two years and updated if changes in procedures
are made. Each laboratory shall have a formal process to track and document review dates
and any revisions made in all quality assurance, quality control, and Standard Operating
Procedure documents. Supporting Records shall be maintained as evidence that these
practices are implemented. The quality assurance, quality control, and Standard Operating
Procedure documents shall be available for inspection by the State Laboratory. Ref: 15A
NCAC 02H .0805 (a) (7).

Comment: The data packages for ICP-OES includes a checkbox that the SIC is within ±10%
but the true value of the SIC is not documented on the laboratory benchsheet. As noted in
Finding D, the preparation of the SIC for ICP-OES is not being documented, so the true value
of the solution is noted only in the SOP.

M. Finding: The MS/MSD recoveries are not calculated correctly for some methods.

Requirement: The volume of spike solution used in MS preparation must in all cases be ≤
5% of the total MS volume. It is preferable that the spike solution constitutes ≤ 1% of the total
MS volume so that the MS can be considered a whole volume sample with no adjustment
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(i.e., volume correction) by calculation necessary. If the spike solution volume constitutes >1%
of the total sample volume, the sample concentration must be adjusted by calculation. Ref:
NC WW/GW LCB Matrix Spiking Policy.

Comment: The spike concentration is 2% of the total volume for Total Organic Carbon (TOC)
and 5% of the total volume for Total Kjeldahl Nitrogen (TKN) and these volumes are not taken
into account during the recovery calculation.

N. Finding: Duplicate analyses are not performed for aqueous Oil & Grease samples.

Requirement: Except where otherwise specified in an analytical method, laboratories shall
analyze five percent of all samples in duplicate to document precision. Laboratories
analyzing fewer than 20 samples per month shall analyze one duplicate during each month
that samples are analyzed. Ref: 15A NCAC 02H .0805 (a) (7) (C).

Comment: The duplicate may be a sample duplicate or an MSD.

O. Finding: The Method Detection Limits (MDLs) for metals by ICP-OES have not been properly
established for all spectral wavelengths.

Requirement: Method Detection Limits (MDLs) must be established for all wavelengths
utilized, using reagent water (blank) fortified at a concentration of two to three times the
estimated instrument detection limit. Ref: EPA Method 200.7, Rev. 4.4 (1994), Section
9.2.4.

Comment: The laboratory submitted their MDLs during the inspection. However, only a single
MDL is listed for each element, and no wavelength is documented. Several elements are
monitored at multiple wavelengths. Please submit an updated MDL list for each
wavelength that is or potentially may be used to analyze Compliance Samples as part
of your Response.

Reporting

P. Finding: Data for Oil & Grease is not being reported to the proper number of significant
figures.

Requirement: Reporting–Report results to three significant figures for HEM and SGT-HEM
found at or above 10 mg/L, and report results to two significant figures for HEM and SGT-
HEM found below 10 mg/L. Ref: EPA Method 1664, Rev. B, February 2010, Section 12.3.

Requirement: Samples–Report results for HEM and SGT-HEM found below the ML as <
5.0 mg/L, or as required by the permitting authority or permit. Ref: EPA Method 1664, Rev.
B, February 2010, Section 12.3.1.

Comment: The laboratory reported data for order #J21110079 below the reporting limit as
< 5 mg/L instead of < 5.0 mg/L.

Mercury – EPA 245.1, Rev. 3.0, 1994 (Aqueous)
Mercury – SW-846 Method 7470 A (Aqueous)

Comment: It was noted during data review that a Mercury sample (ID# 2022008048) analyzed April
5, 2022 had a concentration of 0.043175 µg/L at a forty-fold dilution, giving a final concentration of
1.727 µg/L. Although the QC batch report lists the elevated reporting limit as 2 µg/L, there was no
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qualifier or notation on the data package that the elevated reporting limit was used as the reported
value. No qualifier was attached to the QC batch report that summarizes sample results and QC
results. The sample data was determined to be process control, so data impact was minimal.

Metals – EPA 200.7, Rev. 4.4, 1994 (Aqueous)
Metals – SW-846 6010 D (Aqueous & Non-Aqueous)

Q. Finding: Acceptance criteria have not been established for the internal standards.

Requirement: Unless specified by the method or this Rule, each laboratory shall establish
performance acceptance criteria for all quality control analyses. Each laboratory shall
calculate and document the precision and accuracy of all quality control analyses with each
sample set. When the method of choice specifies performance acceptance criteria for
precision and accuracy, and the laboratory chooses to develop laboratory-specific limits, the
laboratory-specific limits shall not be less stringent than the criteria stated in the approved
method. Ref: 15A NCAC 02H .0805 (a) (7) (A).

Comment: The laboratory is currently using an internal standard to eliminate bias due to
physical interferences for ICP-OES methods. The SOP does not include which elements are
used as internal standards, nor does it provide acceptance criteria for the internal standards.
Since instrument software adjusts the results of the target analytes based on the ratio of the
internal standard response from both the sample and the calibration, it is necessary to set
criteria that will reject data impacted by excessive interferences.

R. Finding: An inconsistency was noted between the SOP and laboratory practice as follows:
the laboratory is running a SIC daily, but the SOP does not address this.

Requirement: Each laboratory shall develop documentation outlining the analytical quality
control practices used for the Parameter Methods included in its Certification, including
Standard Operating Procedures for each certified Parameter Method. Quality assurance,
quality control, and Standard Operating Procedure documentation shall indicate the effective
date of the document and be reviewed every two years and updated if changes in procedures
are made. Each laboratory shall have a formal process to track and document review dates
and any revisions made in all quality assurance, quality control, and Standard Operating
Procedure documents. Supporting Records shall be maintained as evidence that these
practices are implemented. Ref: 15A NCAC 02H .0805 (a) (7).

Comment: The analysis of the daily SIC is not required by EPA 200.7 (Section 7.13) unless
interelement corrections are applied. However, the use of the SIC is required for SW-846
Method 6010D (Sections 7.12 and 9.9), whether or not interelement corrections are being
applied.

Metals – EPA 200.8, Rev. 5.4, 1994 (Aqueous)
Metals – SW-846 6020 B (Aqueous & Non-Aqueous)

Comment: The laboratory is determining which elemental mass to monitor in each mode (Helium
Mode and Hydrogen Mode) by both manufacturer recommendations and instrument performance.

S. Finding: An inconsistency was noted between the SOP and laboratory practice as follows:
the laboratory SOP for analysis of metals by ICP-MS includes techniques for reduction of
interferences that are no longer in use.

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Requirement: Each laboratory shall develop documentation outlining the analytical quality
control practices used for the Parameter Methods included in its Certification, including
Standard Operating Procedures for each certified Parameter Method. Quality assurance,
quality control, and Standard Operating Procedure documentation shall indicate the effective
date of the document and be reviewed every two years and updated if changes in procedures
are made. Each laboratory shall have a formal process to track and document review dates
and any revisions made in all quality assurance, quality control, and Standard Operating
Procedure documents. Supporting Records shall be maintained as evidence that these
practices are implemented. Ref: 15A NCAC 02H .0805 (a) (7).

Comment: The SOP (document #ADMP-ENV-EVS-00125) states that the instrument
reduces interferences by use of a collision/reaction cell operated in three different modes:
Helium, Hydrogen and No-Gas. No-Gas mode is no longer being used, according to the
analyst.

T. Finding: An inconsistency was noted between the SOP and laboratory practice as follows:
the laboratory is analyzing rinses as samples to determine cleanliness of the system between
standards during the calibration process.

Requirement: Each laboratory shall develop documentation outlining the analytical quality
control practices used for the Parameter Methods included in its Certification, including
Standard Operating Procedures for each certified Parameter Method. Quality assurance,
quality control, and Standard Operating Procedure documentation shall indicate the effective
date of the document and be reviewed every two years and updated if changes in procedures
are made. Each laboratory shall have a formal process to track and document review dates
and any revisions made in all quality assurance, quality control, and Standard Operating
Procedure documents. Supporting Records shall be maintained as evidence that these
practices are implemented. Ref: 15A NCAC 02H .0805 (a) (7).

Comment: The normal calibration routine for ICP-MS consists of running several Calibration
Blanks, an RLS, 10, 50, 100, 200 and 500 ppb standards, followed by several “Rinses”, a
Calibration Blank and a 1 ppb standard. Only the Calibration Blank run prior to the 1 ppb
standard is used as a calibration point. The analyst noted that this sequence was performed
to monitor and reduce certain element carryover (e.g., Thallium), but this is not documented
in the SOP. The analytical methods do not require that calibration standards be run in a
specific order.

Comment: The method flexibility of EPA methods permits additional rinses. However, this
must be applied to all samples and standards if the laboratory chooses to continue the
practice. The laboratory must also incorporate the change in procedure into the SOP.

U. Finding: The MDL does not support the current reporting level for Iron.

Requirement: The MDL is defined as the minimum measured concentration of a substance
that can be reported with 99% confidence that the measured concentration is distinguishable
from method blank results. Ref: Code of Federal Regulations, Title 40, Part 136; Federal
Register Vol. 82, No. 165, August 28, 2017; Appendix B–Definition and Procedure for the
Determination of the Method Detection Limit–Revision 2.

Comment: The Reporting Limit for Iron is currently < 2 µg/L. The current MDL for Iron is 2.38
µg/L. The laboratory must either elevate the reporting level above the MDL or repeat the MDL
study with results determined to be less than the reporting level.

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Anions (Br-, Cl-, F-, SO42-, NO3+NO2) – EPA 300.0, Rev. 2.1, 1993 (Aqueous)
Anions (Cl-, F-, SO42-, NO3+NO2) – SW-846 9056 A (Aqueous)

V. Finding: The continuing calibration verification is not always mid-range.

Requirement: Instrument Performance Check Solution (IPC) - For all determinations the
laboratory must analyze the IPC (a mid-range check standard) and a calibration blank
immediately following daily calibration, after every tenth sample (or more frequently, if
required) and at the end of the sample run. Ref: EPA Method 300.0, Rev. 2.1 (1993), Section
9.3.4.

Requirement: Verify the accuracy of the working calibration curve on each working day, or
whenever the anion eluent composition or strength is changed, and for every batch of 10 or
less samples, through the analysis of a continuing calibration verification (CCV) standard. The
CCV should be made from the same material as the initial calibration standards at or near
mid-range. The acceptance criteria for the CCV standard should be ± 10% of its true value for
the calibration to be considered valid. Ref: EPA SW-846 Test Methods for Evaluating Solid
Waste, Physical/Chemical Methods; 3rd Edition, Method 9056 A. Rev. 1, February 2007,
Section 10.7.

Requirement: The NC WW/GW Laboratory Certification Branch must confirm that analytical
data is valid by reviewing the QA/QC data generated during the sampling and analysis
procedures when implementing SW-846 methods in order to be assured that scientifically
sound decisions are made which will be protective of human health and the environment. To
promote consistency with the use of SW-846 methods and to assure generation of data of
known quality, the minimum recommended quality control benchmarks in the methods will be
considered the minimum QA/QC requirements. For example, where a method states,
“Documenting the effect of the matrix on target analyte measurements should include the
analysis of at least one matrix spike and one duplicate unspiked samples or one matrix
spike/matrix spike duplicate pair.”, the laboratory must analyze at least one matrix spike and
one duplicate unspiked sample or one matrix spike/matrix spike duplicate pair. Laboratories
may adopt more stringent QC acceptance criteria for method performance but may not omit
or use less stringent criteria than that stated in SW-846 methods. Ref: NC WW/GW LCB SW-
846 Method Implementation Policy.

Comment: The laboratory uses two instruments for Anion analysis "System 7" and "System
8". A technician from the instrument manufacturer programmed "System 7" to analyze
continuing calibration verification (CCV) standards at a concentration of 2 mg/L, which does
not meet the requirement of a mid-range check standard. The current calibration range is 0.1
to 10 mg/L. The CCV standards analyzed on "System 8" are 5 mg/L. The initial calibration
verification (ICV) is mid-range on both instruments as required.

W. Finding: The laboratory is diluting the MS and MSD before adding the spiking solution.

Requirement: The concentration of the spiked samples must be bracketed by the calibration
range. If the spiked sample result is over the calibration range, the spiked sample must be
diluted and re-analyzed. It is not acceptable to dilute the sample first and then add the spike
solution so as not to affect bias attributed to matrix. Ref: NC WW/GW LCB Matrix Spiking
Policy.

Comment: The analyst has concerns about samples that are considerably above the
calibration range and need significant dilutions before the spike solution is even added.

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Comment: If the concentration of a spiked sample is considerably above the calibration
range, the laboratory may choose to dilute the spiked sample to determine if the concentration
of the spiking solution needs to be increased. In this situation, the unspiked sample must be
spiked with a higher concentration spiking solution and then diluted to bring the value within
the calibration range of the instrument.

Nitrogen, Ammonia – EPA 350.1, Rev. 2.0, 1993 (Aqueous)
Nitrogen, Nitrate + Nitrite – EPA 353.2, Rev. 2.0, 1993 (Aqueous)
Nitrogen, Total Kjeldahl – EPA 351.2, Rev. 2.0, 1993 (Aqueous)

Comment: The analyst trained to perform these methods is currently on leave and the laboratory
has been sending samples to a contract laboratory during this timeframe. The plan is to bring these
analyses back into the laboratory after the analyst returns and performs any demonstrations of
capability that are required.

Recommendation: A calibration curve is analyzed every analysis day for these methods and each
standard is back-calculated with the percent error from the expected concentration documented. The
SOPs for the methods all state that the acceptance criterion for the minimum reporting limit standard
is ±50% of the reporting limit. It is recommended that the Data Review Checklist for each method
include a check for the back-calculated reporting limit standard to demonstrate that the analyst would
be aware of any results that do not meet the acceptance criterion.

Organic Carbon, Total – Standard Methods, 5310 C-2014 (Aqueous)

X. Finding: The calibration points are not compared to the curve and recalculated.

Requirement: Compare each calibration point to the curve and recalculate its concentration.
If any recalculated values are not within the method's acceptance criteria—≤3 times the MRL
±50%; between 3 and 5 times the MRL ±20%; or >5 times the MRL ±10%, unless otherwise
specified in individual methods—identify the source of any outlier(s) and correct before sample
quantitation. Ref: Standard Methods, 5020 B-2017. (1) (b).

Y. Finding: The laboratory is analyzing two replicate injections.

Requirement: Sample injection: See 5310B.4c. Ref: Standard Methods, 5310 C-2014. (4)
(c).

Requirement: Repeat injection until at least three replicate measurements are reproducible
to within ±10%. Ref: Standard Methods, 5310 B-2014. (4) (c).

Z. Finding: The laboratory is not performing a TOC carryover check.

Requirement: TOC carryover check—Immediately following the analysis of the highest
calibration standard, analyze a blank. The concentration of the blank must be <1/2 of the MRL.
If the blank has a value >1/2 of the MRL, then the highest calibration point must be lowered
until the blank immediately following the point has a value <1/2 of the MRL. Analyze the high
calibration point/blank pair at the beginning of every analytical day to verify that carryover is
not occurring. Ref: Standard Methods, 5310 A-2014. (5) (a) (4).

AA. Finding: The continuing calibration check is not being varied between low, medium and high-
range concentrations.

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Requirement: Continuing calibration check—After every 10 samples, analyze one of three
calibration check samples—low-range, mid-range, and high-range standard concentrations—
on a rotating basis. The low-range standard should be at or below the minimum reporting
level. The low-range sample should agree within 50% of the true value, and the mid- and high-
range samples should agree within 15%. Ref: Standard Methods, 5310 A-2014. (5) (b) (7).

Comment: The laboratory's SOP states that the concentration is to be varied. However, there
is no frequency, concentration or acceptance criteria specified and the procedure has not
been put into practice.

Turbidity – EPA 180.1, Rev. 2.0, 1993 (Aqueous)

BB. Finding: The Instrument Performance Check (IPC) standard is not at a mid-range
concentration.

Requirement: For all determinations, the laboratory must analyze the IPC (a mid-range check
standard) and a calibration blank immediately following daily calibration, after every tenth
sample (or more frequently, if required) and at the end of the sample run. Ref: EPA Method
180.1, Rev. 2.0 (1993), Section 9.3.2.

Comment: Laboratory practice is to verify calibration with a standard of 15 NTU immediately
after calibration, rather than a mid-range standard of 20 NTU. The laboratory is calibrating
with standards up to a concentration of 2000 NTU.

Recommendation: It is recommended that the laboratory tighten the range of calibration
standards used if they wish to continue using a 20 NTU standard as the IPC. Alternatively,
they may use an IPC with a value of 1000 NTU and continue to calibrate with standards up to
a concentration of 2000 NTU.

IV. PAPER TRAIL INVESTIGATION:

The paper trail consisted of comparing original records (e.g., laboratory benchsheets, logbooks, etc.) and
QC Batch Reports for permittees. Data were reviewed for Jobs J21110063 and J2110079. No
transcription errors were observed. The facility appears to be doing a good job of accurately transcribing
data.

V. CONCLUSIONS:

Correcting the above-cited Findings and implementing the Recommendation(s) will help this laboratory to
produce quality data and meet Certification requirements. The inspector would like to thank the staff for
their assistance during the inspection and data review process. Please respond to all Findings and
include supporting documentation, implementation dates and steps taken to prevent recurrence
for each corrective action.

Report prepared by: Michael Cumbus Date: August 4, 2022
Report reviewed by: Jason Smith Date: August 5, 2022