#245_2023_0425_TLH_FINAL

NC Department of Environmental Quality | Division of Water Resources | Laboratory Certification Branch
4405 Reedy Creek Road | 1623 Mail Service Center | Raleigh, North Carolina 27699-1623
919-733-3908

June 14, 2023

245
Ms. Ashton Weller
Perdue Foods - Lewiston
P.O. Box 460
Lewiston Woodville, NC 27849

Subject: North Carolina Wastewater/Groundwater Laboratory Certification Branch (NC
WW/GW LCB) Maintenance Inspection

Dear Ms. Weller:

Enclosed is a report for the inspection performed on April 25, 2023 by Thomas Halvosa and Beth
Swanson. I apologize for the delay in getting this report to you. Where Finding(s) are cited in this
report, a response is required. Within thirty days, please supply this office with a written item for
item description of how these Finding(s) were corrected. Please describe the steps taken to
prevent recurrence and include an implementation date for each corrective action. If the Finding(s)
cited in the enclosed report are not corrected, enforcement actions may be recommended. For
Certification maintenance, your laboratory must continue to carry out the requirements set forth
in 15A NCAC 02H .0800.

A copy of the laboratory’s Certified Parameter List at the time of the audit is attached. This list will
not reflect any changes made during the audit. Copies of the checklists completed during the
inspection may be requested from this office. Thank you for your cooperation during the
inspection. If you have questions or need additional information, please contact me at (919) 733-
3908 Ext. 259.

Sincerely,

Beth Swanson
Technical Assistance & Compliance Specialist
Division of Water Resources

Attachment
cc: Todd Crawford, Thomas Halvosa, #245

On-Site Inspection Report

LABORATORY NAME: Perdue Foods - Lewiston
NPDES PERMIT #: NC0023116, NC0028835
WATER QUALITY PERMIT #: WQ0004867, WQ0006058
ADDRESS: 3539 Governors Road
Lewiston Woodville, NC 27849
CERTIFICATE #: 245
DATE OF INSPECTION: April 25, 2023
TYPE OF INSPECTION: Industrial Maintenance
AUDITOR(S): Tom Halvosa and Beth Swanson

LOCAL PERSON(S) CONTACTED:

Ashton Weller, Tim Mizelle, Marcia Hicks and Ginger Ruffins

I. INTRODUCTION:

This laboratory was inspected by representatives 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 and well organized and has all the equipment necessary to perform the analyses.
Laboratory personnel communicate well with sample collectors and coordinate sample analyses
effectively to manage workload and holding times. Staff were forthcoming and responded well to
suggestions from the auditor.

All required Proficiency Testing (PT) Samples for the 2023 PT Calendar Year have not yet been analyzed.
The laboratory is reminded that results must be received by this office directly from the vendor by September
30, 2023.

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
May 1, 2024.
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The laboratory is 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 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.

Contracted analyses are performed by Waypoint Analytical - Greenville (Certification #10).

The following locations correspond to these permits: Town of Lewiston (NC0023116), Perdue Foods
(NC0028835) and Halifax Hatchery (WQ0006058).

Approved Procedure documents for the analysis of the facility’s currently certified Field Parameters were
provided at the time of the inspection.

III. FINDINGS, REQUIREMENTS, COMMENTS AND RECOMMENDATIONS:

Documentation

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: There were several instances of incorrect error corrections such as write overs
and no dates or initials of the responsible individual.

B. Finding: The Total Residual Chlorine (TRC), Conductivity, Dissolved Oxygen (DO), pH and
Temperature laboratory benchsheets are lacking required documentation: the method or
Standard Operating Procedure reference.

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: This Finding pertains to all Field Parameter benchsheets for Halifax Hatchery and
the Town of Lewiston as well as the Purdue Foods benchsheets for TRC and Temperature.

C. Finding: The Ammonia, BOD, TRC, Conductivity, DO, Oil & Grease (O&G), pH, Total
Dissolved Residue (TDR) and Total Residue (TR) and Temperature laboratory benchsheets
are lacking required documentation: the laboratory identification.

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

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Comment: This Finding pertains to all Field Parameter benchsheets for Halifax Hatchery and
the Town of Lewiston as well as the Purdue Foods benchsheets for Ammonia, BOD,
Conductivity, O&G, TDR and TR.

D. Finding: The BOD, TRC, Conductivity, DO, pH and Temperature laboratory benchsheets are
lacking required documentation: the 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. Each item shall be recorded each time samples are analyzed. Ref: 15A NCAC
02H .0805 (a) (7) (F) (iii).

Comment: This Finding pertains to all Field Parameter benchsheets for all facilities.

Comment: For BOD analyses, the laboratory documents the pH meter calibration on a
separate log. The pH meter calibration is not traceable to the analysis without instrument
identification on the BOD benchsheet.

E. Finding: The TRC, Conductivity, DO, pH and Temperature laboratory benchsheets are
lacking required documentation: the signature or initials of the analyst.

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

Comment: This Finding pertains to all Field Parameter benchsheets for Halifax Hatchery and
the Town of Lewiston.

F. Finding: The BOD, TRC, Conductivity, DO, pH, Total Suspended Residue and Temperature
laboratory benchsheets are lacking required documentation: the proper 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 samples are analyzed. Ref: 15A NCAC 02H
.0805 (a) (7) (F) (xii).

Comment: This Finding pertains to all Field Parameter benchsheets for Halifax Hatchery and
the Town of Lewiston.

Comment: The Town of Lewiston and the Purdue Foods BOD benchsheets lack units of
measure (S.U.) for pH values. The Purdue Foods pH benchsheet lacks units of measure
(S.U.) in the calibration section.

Comment: The laboratory is not consistently documenting units of the residue oven
temperature.

G. Finding: The laboratory is not documenting all traceability information for purchased
materials, reagents and standards.

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
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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 receipt log lacks the date opened.

H. Finding: The laboratory does not document all required traceability information for standards
and reagents.

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 standards and reagents log does not include vendor names.

I. Finding: Preparation of the Oil & Grease Ongoing Precision and Recovery (OPR) standard
is not being documented.

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.

J. Finding: The BOD and DO laboratory benchsheets are lacking required documentation:
barometric pressure and salinity used for meter calibration.

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Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: The following must be documented in indelible ink whenever sample analysis
is performed: Calibration variables (temperature, elevation or barometric pressure [in mmHg],
and salinity). Ref: NC WW/GW LCB Approved Procedure for the Analysis of Dissolved
Oxygen (DO).

Requirement: Determination of Initial DO: Use the Azide modification of the iodometric
method (Section 4500-O.C), membrane-electrode method (Section 4500-O.G), or optical-
probe method (Section 4500-O.H) to determine initial DO on all sample dilutions, dilution water
blanks, and, where appropriate, seed controls. Ref: Standard Methods, 5210 B-2016. (5) (g).

Requirement: Calibrate probe in accordance with manufacturer's instructions to obtain the
guaranteed precision and accuracy. Ref: Standard Methods, 4500 O H-2016. (4).

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

Comment: A note on both benchsheets stating what salinity value is programmed into the
meter is sufficient. If applicable, the laboratory’s SOP would state that zero is used as the
default since the salinity of the samples is ≤ 9 ppt.

K. Finding: The laboratory is lacking a sufficiently documented training program.

Requirement: Each laboratory shall develop and implement a documented training program
that includes documentation that: staff have the education, training, experience, or
demonstrated skills needed to generate quality control results within method-specified limits
and meet the requirements of these Rules; staff have read the laboratory quality assurance
manual and applicable Standard Operating Procedures; and staff have obtained acceptable
results on Proficiency Testing Samples pursuant to Rule .0803(1) of this Section or other
demonstrations of proficiency (e.g., side-by-side comparison with a trained analyst,
acceptable results on a single-blind performance evaluation sample, an initial demonstration
of capability study prescribed by the method). Ref: 15A NCAC 02H .0805 (a) (7) (P).

Comment: The laboratory needs a sign off section in the Training SOP where the analyst can
confirm they have read and understood the SOP for each parameter method.

Proficiency Testing

L. Finding: The laboratory does not have a documented plan for PT procedures.

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
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Procedure documents shall be available for inspection by the State Laboratory. Ref: 15A
NCAC 02H .0805 (a) (7).

Requirement: Laboratories must have a documented plan [this is usually detailed in the
laboratory’s Quality Assurance Manual or may be a separate Standard Operating Procedure
(SOP)] of how they intend to cover the applicable program requirements for Proficiency
Testing per their scope of accreditation. This plan shall cover any commercially available PT
Samples and any inter-laboratory organized studies, as applicable. The plan must also
address the laboratory’s process for submission of PT Sample results and related Corrective
Action Reports (CARs). Ref: Proficiency Testing Requirements, January 1, 2023, Revision 6,
Section 3.0.

Requirement: SOPs must address situations where the instructions from the Accredited PT
Provider for the preparation, analysis or result calculations would constitute a deviation from
the laboratory’s routine procedure. Examples of this may include how low-level PT Samples
will be analyzed, including concentration of the sample or adjustment of the normality of a
titrant. These instructions shall be followed when the concentration of a PT Sample is below
the range of their routine analytical method. Instructions shall also be included in the
laboratory’s SOP for how high-level PT Samples will be analyzed, including preparation of
multiple dilutions of the sample. These instructions will be followed when the concentration of
a PT Sample is above the range of their routine analytical method. Ref: Proficiency Testing
Requirements, January 1, 2023, Revision 6, Section 3.0.

M. Finding: Additional QC beyond what is routine for Compliance Samples is being analyzed
with PT Samples.

Requirement: Laboratories are required to analyze an appropriate PT Sample by each
Parameter Method and in each associated matrix on the laboratory’s CPL. The same PT
Sample may be analyzed by one or more methods. Laboratories shall conduct the analyses
in accordance with their routine testing, calibration and reporting procedures, unless otherwise
specified in the instructions supplied by the Accredited PT Sample Provider. This means that
they are to be logged in and analyzed using the same staff, sample tracking systems, standard
operating procedures including the same equipment, reagents, calibration techniques,
analytical methods, preparatory techniques (e.g., digestions, distillations and extractions) and
the same quality control acceptance criteria. PT Samples shall not be analyzed with additional
quality control. They are not to be replicated beyond what is routine for Compliance Sample
analysis. Although, it may be routine to spike Compliance Samples, it is neither required, nor
recommended, for PT Samples. PT sample results from multiple analyses (when this is the
routine procedure) must be calculated in the same manner as routine Compliance Samples.
Ref: Proficiency Testing Requirements, January 1, 2023, Revision 6, Section 3.6.

Comment: The laboratory sometimes analyzes a known PT Sample on the same day as the
unknown PT Sample.

Quality Assurance/Quality Control

Comment: The laboratory is sometimes analyzing duplicates for Field Parameters which is not
required.

N. Finding: SOPs have not been updated for all of the methods included on the laboratory’s
Certified Parameters Listing (CPL).

Requirement: Each laboratory shall have a documented analytical quality assurance and
quality control program. Each laboratory shall have a copy of each approved test, analysis,
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measurement, or monitoring procedure being used in the laboratory. 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 Oil and Grease SOP has not been reviewed and revised since May 21, 2015.

O. Finding: Precision (e.g., relative percent difference) and/or accuracy (e.g., percent recovery)
of QC results are not consistently calculated, evaluated and/or documented to demonstrate
the analytical process is in control and the established acceptance criteria are met.

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 TRC and pH benchsheets for Halifax Hatchery and the Town of Lewiston lack
all quality control assessments.

Comment: The Purdue Foods benchsheets for TRC, Conductivity and TSR lack all quality
control assessments.

Comment: The benchsheet for the Town of Lewiston TSR samples does not include all QC
assessments. The laboratory analyzes the Town of Lewiston and Perdue Lewiston Plant
samples at the same time, but on separate benchsheets. The laboratory duplicates one of the
Perdue Lewiston Plant samples and the Town of Lewiston benchsheet does not include the
duplicate analysis so it appears that duplicates are not included for Town of Lewiston samples.

Comment: The balance calibration log for Oil and Grease does not include the acceptance
criteria for the two required weights.

P. Finding: Precision of the Fecal Coliform duplicates is not consistently evaluated to
demonstrate the analytical process is in control and the established acceptance criteria are
met.

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).

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Comment: The Fecal Coliform benchsheets for the Town of Lewiston and Perdue Foods do
not include the duplicate acceptance criterion.

Comment: The laboratory’s Fecal Coliform SOP assigns a duplicate acceptance criterion of
±10 MPN/100 mL. Data review showed that most Fecal Coliform results for both Purdue
Foods and the Town of Lewiston were below 10 MPN/100 mL. Where these instances were
noted, no QC evaluation was documented and the benchsheet does not include the
acceptance criterion.

Recommendation: IDEXX recommends basing duplicate acceptance on the 95%
confidence range. Looking at the sample and duplicate ranges, they are acceptable as long
as those 2 ranges overlap. Go to the following website to download a program where you can
enter results and it will calculate the MPN and 95% confidence range-
https://www.idexx.com/en/water/resources/mpn-generator/. Alternately, a chart that contains
all possible MPN results with the corresponding 95% confidence levels can be found on the
technical assistance portion of our website. RPD may also be used for the acceptance
criterion. When calculating the RPD, use the arithmetic mean.

Conductivity – Standard Methods, 2510 B-2011 (Aqueous)

Q. Finding: The Automatic Temperature Compensator (ATC) check is not being performed.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: The ATC must be verified prior to initial use and annually (i.e., 12 months)
thereafter at two temperatures by analyzing a standard or sample at 25°C (i.e., the
temperature to which conductivity values are reported) and a temperature(s) that brackets the
temperature ranges of the environmental samples routinely analyzed. This may require the
analysis of a third temperature reading that is > 25°C (see #3 below). The manner in which
the ATC is verified may depend upon the meter’s capabilities and the manufacturer’s
instructions. Ref: NC WW/GW LCB Approved Procedure for the Analysis of Specific
Conductance (Conductivity).

R. Finding: The laboratory is not analyzing a second-source calibration verification check
standard.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: Analyze and document a second-source calibration verification check
standard prior to compliance sample analysis. It is recommended that this standard value
approximate (may be higher or lower than the calibration standard, as applicable) the
expected range of sample values measured. The value obtained for the calibration verification
check-standard must read within 10% of the true value of the calibration verification check
standard. If the obtained value is outside of the ±10% range, corrective action must be taken.
Ref: NC WW/GW LCB Approved Procedure for the Analysis of Specific Conductance
(Conductivity).

Comment: Please note that Conductivity standards may not be diluted.

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Conductivity – Standard Methods, 2510 B-2011 (Aqueous)
Dissolved Oxygen – Standard Methods, 4500 O H-2016 (Aqueous)

S. Finding: The laboratory is not performing a post-analysis calibration verification when
performing multiple sample analyses.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: When performing multiple sample analyses, a post-analysis calibration
verification must be analyzed at the end of the run. It is recommended that a mid-day or a
mid-batch calibration verification be performed when samples are analyzed over an extended
period of time. The value obtained for the post-analysis calibration verification check-standard
must read within 10% of the standard’s true value. If the obtained value is outside of the ±10%
range, corrective action must be taken. If recalibration is necessary, all samples analyzed
since the last acceptable calibration verification must be reanalyzed, if possible. If samples
cannot be reanalyzed, the data must be qualified. Ref: NC WW/GW LCB Approved Procedure
for the Analysis of Specific Conductance (Conductivity).

Requirement: When performing analyses at multiple sample sites, the meter must be
calibrated at each sample site prior to analysis or a post-analysis calibration verification must
be performed at the end of the run, regardless of meter type. The calculated theoretical DO
value must verify the meter reading within ±0.5 mg/L. If the meter verification does not read
within ±0.5 mg/L of the theoretical DO, corrective action must be taken. If the meter is not
calibrated at each sample site, it is recommended that a mid-day calibration be performed
when samples are extended over an extended period of time. Ref: NC WW/GW LCB
Approved Procedure for the Analysis of Dissolved Oxygen (DO).

Comment: The laboratory is analyzing upstream and downstream sampling locations without
performing a post-analysis calibration verification afterwards.

Total Residual Chlorine – Standard Methods, 4500 Cl E-2011 (Aqueous)

T. Finding: Values less than the established reporting limit are being reported on the Discharge
Monitoring Report (DMR).

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: The minimum reporting level (MRL) is set at or above the lowest standard used
in the analysis. Quantitation at the MRL must be verified initially and at least quarterly
(preferably daily) by analyzing a QC sample. Ref: NC WW/GW LCB Approved Procedure for
the Analysis of Total Residual Chlorine (Low-Level Amperometric Forward Titration by SM
4500 Cl E-2011).

Comment: The laboratory consistently reports <25 µg/L on the Purdue Foods DMR. The
laboratory analyzes a weekly 30 µg/L chlorine standard which establishes that value as the
MRL. Since the permit limit for this facility is 28 µg/L, the laboratory agreed to analyze an MRL
at 15 µg/L. This would cover their limit as well as the Town of Lewiston’s 17 µg/L permit limit
which they also analyze.

U. Finding: The laboratory is not analyzing a Daily Check Standard.
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Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: Analyze a freshly prepared Daily Check Standard in the range of 10 to 100
μg/L either from a commercially prepared standard or user-prepared standard. If commercially
prepared chlorine standard solutions with a stated range and average value are used, the
average value must be used for the true value of the standard. Ref: NC WW/GW LCB
Approved Procedure for the Analysis of Total Residual Chlorine (Low-Level Amperometric
Forward Titration by SM 4500 Cl E-2011).

V. Finding: Purchased low-strength standard phenylarsine oxide (PAO) titrant is not being
standardized monthly once it has been opened.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: The low-strength standard phenylarsine oxide (PAO) titrant must be
standardized initially when prepared by the laboratory and every month thereafter (see
Appendix A for standardization procedure). Purchased titrant is not required to be
standardized initially when the certificate of analysis is retained but must be standardized
monthly once it has been opened. All standardizations must be documented. CAUTION:
phenylarsine oxide is a cancer-suspect agent. Ref: NC WW/GW LCB Approved Procedure
for the Analysis of Total Residual Chlorine (Low-Level Amperometric Forward Titration by SM
4500 Cl E-2011).

pH – Standard Methods, 4500 H+ B-2011 (Aqueous)

Comment: The laboratory calibrates and analyzes a Check Buffer for the Hach Pocket Pro pH meter
(used for the Town of Lewiston and the Halifax Hatchery pH analyses) in the laboratory and then
transports it over a mile or more to analyze Compliance Samples.

Recommendation: It is recommended that the laboratory calibrate and analyze the Check Buffer at
the sample locations (Town of Lewiston and Halifax Hatchery) rather than in the laboratory. The
Approved Procedure for the Analysis of pH currently states that if analyses are conducted at multiple
sample locations, then a post-analysis buffer check is required. Although the wording is not clear, the
intent is to consider the location where the calibration is conducted as the first location. This will be
clarified in an upcoming revision to the Approved Procedure for the Analysis of pH and it is
recommended that the laboratory institute the change proactively.

Temperature – Standard Methods, 2550 B-2010 (Aqueous)

W. Finding: The compliance temperature-measuring device is not checked at two temperatures
that bracket the range of observed sample temperatures.

Requirement: The State Laboratory may develop Approved Procedures for Field
Parameters based upon the methods in any of the sources referenced in Parts(a)(1)(A)
through (F) of this Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: To check a compliance temperature-measuring device, compare readings
at two temperatures that bracket the range of compliance samples routinely analyzed
against a Reference Temperature-Measuring Device and record all four readings. The
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readings from both devices must agree within 0.5ºC. If they do not, the device may not be
used for temperature compliance monitoring. Ref: NC WW/GW LCB Approved Procedure
for the Analysis of Temperature.

Comment: The laboratory only checks the meter at one temperature.

Bacteria - Coliform Fecal – IDEXX Colilert® 18 (MPN) (Aqueous)

Recommendation: The laboratory reports Fecal Coliform results to 0.1 MPN/100 mL. It is
recommended that the laboratory report results in whole numbers.

X. Finding: The Certificate of Analysis documenting the sterility of each lot of purchased sample
bottles is not being maintained.

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

Requirement: Minimally test for sterility one sample bottle per batch sterilized in the
laboratory, or at a set percentage such as 1 to 4%. This is performed by adding sterile
dilution/rinse water to the bottle after sterilization and then subsequently analyzing it as a
sample. Document results. If sample bottles or bags are purchased pre-sterilized, verification
of sterilization is not required if the laboratory maintains copies of the Certificate of Analysis
from the vendor. Ref: NC WW/GW LCB Bacteriological Sample Bottle Sterility Test Policy.

BOD – Standard Methods, 5210 B-2016 (Aqueous)

Y. Finding: Extra nutrient, mineral, and buffer solutions are not added to the incubation bottles
containing more than 67% (i.e., > 201 mL) sample.

Requirement: When a bottle contains >67% of the sample after dilution, nutrients may be
limited in the diluted sample and subsequently reduce biological activity. In such samples, add
the nutrient, mineral, and buffer solutions (5210B.3a-d) directly to diluted sample at a rate of
1 mL/L (0.30 mL/300-mL bottle), or use commercially-prepared solutions designed to dose
the appropriate bottle size. Ref: Standard Methods, 5210 B-2016. (5) (c) (2).

Z. Finding: Documentation does not demonstrate that the initial DO for BOD analysis is
measured within 30 minutes of sample preparation. This is considered pertinent data.

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).

Requirement: After preparing dilution, measure initial DO within 30 min. Ref: Standard
Methods, 5210 B-2016. (5) (g).

AA. Finding: A duplicate sample dilution is not always analyzed daily.

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).

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Requirement: As a minimum, include one duplicate sample or one LFM duplicate with each
sample set (batch) or on a 5% basis, whichever is more frequent, and process it independently
through the entire sample preparation and analysis. Ref: Standard Methods, 5020 B-2017.
(8).

Requirement: Duplicates or LFMD of the sample will be run. Ref: Standard Methods, 5020
B-2017. Table 5020:I, Footnote 2.

Comment: Since there are no LFMs in the BOD method, a duplicate must be analyzed. Only
the duplicate of one dilution of the three set up is needed to meet the minimum requirement.

Comment: There were no duplicate dilutions on the Town of Lewiston benchsheet for January
25, 2023.

BB. Finding: The laboratory is not properly reporting the BOD results.

Requirement: The reporting limit for BOD5/CBOD5 is 2 mg/L. Only bottles giving a
minimum Dissolved Oxygen (DO) depletion of 2.0 mg/L and a residual DO of 1.0 mg/L after
5 days of incubation are considered to produce valid data. It is not acceptable to elevate
the reporting limit and report as less than the value that would have been obtained if the
dilution had depleted the required 2.0 mg/L. It is required that the data be flagged as a
quality control failure if it does not deplete the 2.0 mg/L. The only exception to this is when
a 100% sample does not deplete 2.0 mg/L. In this case, report the value as <2.0 mg/L
without qualification. Ref: NC WW/GW LCB BOD5/CBOD5 Elevated Reporting Limit Policy.

Comment: On the January 25, 2023 Town of Lewiston benchsheet, the laboratory used
an effluent result of an 80% dilution that did not deplete 2 mg/L or greater to calculate the
final BOD result of 0.51 mg/L. The other dilution on that day was set at 100% and should
have been the only result used, however, since it depleted <2 mg/L it should have been
reported as <2 mg/L.

Nitrogen, Ammonia – Standard Methods, 4500 NH3 D-2011 (Aqueous)

CC. Finding: The laboratory is not analyzing an LFMD.

Requirement: As a minimum, include one duplicate sample or one LFM duplicate with each
sample set (batch) or on a 5% basis, whichever is more frequent, and process it independently
through the entire sample preparation and analysis. Ref: Standard Methods, 4020 B-2014. (8)
and Table 4020:I.

Comment: The laboratory analyzes a sample duplicate. Table 4020:I states that an LFM and
LFMD are required in place of a sample duplicate. When the LFMD is instituted, a separate
sample duplicate is not required.

DD. Finding: The laboratory is not adjusting the sample concentration in the percent recovery
calculation when the spike volume is >1% of the total sample volume.

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
(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.

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Comment: The laboratory adds 5 mL of spiking solution to 250 mL of sample.

Oil & Grease – EPA 1664, Rev. B (Aqueous)

Comment: The laboratory does not analyze Oil & Grease for compliance reporting. The only data
reviewed was the 2022 PT Sample data.

EE. Finding: The laboratory does not analyze an OPR standard with each analytical batch.

Requirement: Each analytical batch of 20 or fewer samples must be accompanied by a
laboratory blank (Section 9.4), an ongoing precision and recovery sample (OPR, Section 9.6),
and a matrix spike, (Section 9.3), resulting in a minimum of four analyses (1 sample, 1 blank,
1 OPR, and 1 MS) and a maximum of 23 analyses (20 field samples, 1 blank, 1 OPR, and 1
MS) in the batch. Ref: EPA method 1664 Rev. B, Section 18.2.2.

Comment: The laboratory analyzes a standard each month and this did not coincide with the
PT Sample analysis.

FF. Finding: The laboratory does not correctly calculate the results.

Requirement: n-Hexane extractable material–Calculate the concentration of HEM (“oil and
grease”) in the sample per the following equation:

HEM (mg/L) = [Wh (mg)] / [Vs (L)]
where:
Wh = Weight of extractable material from Section 11.4.4.1 (mg)
Vs = Sample volume from Section 11.4.5 (L). Ref: EPA method 1664 Rev. B, Section 12.1.

Comment: The laboratory uses the following equation to calculate results: Oil and Grease =
(A-B) *1000/mL sample, where A = sample result and B = blank result. The blank is not to be
subtracted from the sample value.

Residue, Total - Standard Methods, 2540 B-2015 (Aqueous)
Residue, Dissolved 180 C - Standard Methods, 2540 C-2015 (Aqueous)

Comment: Total Residue (TR) and Total Dissolved Residue (TDR) are not analyzed for compliance
reporting. The only data reviewed was the 2022 PT Sample data.

Comment: 100 mL of water is used for the blank in both analyses. Only a dry dish is required for TR
and only 30 mL of water is required for TDR.

GG. Finding: The laboratory does not analyze a Laboratory-Fortified Blank (LFB) with each batch.

Requirement: Include one laboratory-fortified blank (LFB) per batch of 20 samples for all
tests except settleable solids (2540F) and total, fixed, and volatile solids in solid and semisolid
samples (2540G). Plot the percent recoveries on a control chart for laboratory evaluation.
Laboratories may purchase known standards or prepare in-house working controls for use.
Ref: Standard Methods, 2540 A-2015. (5).

Comment: The laboratory analyzes a standard each month and this did not coincide with the
PT Sample analysis.

HH. Finding: The laboratory is not drying the sample to constant weight.

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Requirement: Repeat cycle (drying, cooling, desiccating, and weighing) until weight change
is <0.5 mg. Ref: Standard Methods, 2540 C-2015. (3) (d).

Requirement: Repeat cycle (drying for ≥1 h, cooling, desiccating, and weighing) until weight
change is <0.5 mg. Ref: Standard Methods, 2540 B-2015. (3) (c).

Residue, Suspended - Standard Methods 2540 D-2015 (Aqueous)

Comment: The laboratory updated their benchsheet and instituted the second drying cycle for
constant weight after receiving checklists for the inspection.

Comment: On the benchsheet titled "Daily Drying Cycle Verification for TSS" both criteria listed for
constant weight verification are incorrect. The benchsheet states "less than 4 mg or 5%, whichever is
less" but the method requirement is less than or equal to 5 mg. The other analysis benchsheet
documents the correct constant weight requirement and that is the requirement being used.

Recommendation: It is recommended that the laboratory rotate the duplicate analysis to include the
Town of Lewiston influent and effluent. Currently the laboratory only duplicates the Perdue Lewiston
Plant effluent which does not meet the minimum weight gain.

Recommendation: It is recommended that the final weight of the dried residue plus filter be used
for the results calculation. The laboratory is currently using the first dried residue plus filter weight for
the results calculation. No instances where the first and second weight did not meet the constant
weight criterion were found, however, the first weight could not be used if there was a difference >5
mg in the first two weights, since it would not be one of the constant weights.

II. Finding: The laboratory is not analyzing a volume of sample to yield a minimum of 2.5 mg
dried residue.

Requirement: Choose sample volume to yield between 2.5 and 200 mg dried residue. If
volume filtered fails to meet minimum yield, increase sample volume up to 1 L. If filtration takes
>10 min to complete, increase filter size or decrease sample volume. Ref: Standard Methods,
2540 D-2015 (3) (b).

Comment: The volume of sample analyzed is 150 mL for Lewiston Plant effluent, 150 mL for
Town of Lewiston effluent, and 30 mL for Town of Lewiston influent. The minimum weight gain
is rarely met for any of the sample locations.

JJ. Finding: The laboratory is not basing the reporting limit on the minimum weight gain required
by the method.

Requirement: The minimum weight gain allowed by any approved method is 2.5 mg.
Choose sample volume to yield between 2.5 and 200 mg dried residue. This establishes a
minimum reporting value of 2.5 mg/L when 1000 mL of sample is analyzed. If complete
filtration takes more than 10 minutes increase filter diameter or decrease sample volume. In
instances where the weight gain is less than the required 2.5 mg, the value must be reported
as less than the appropriate value based upon the volume used. Ref: NC WW/GW LCB Total
Suspended Solids Reporting Limit Policy.

Comment: The laboratory is reporting values below the elevated reporting limit. At Lewiston
Mill, the sample volume analyzed is 150 mL, which has an elevated PQL of 16.7 mg/L (round
to 17 mg/L). At Town of Lewiston, the volume is 250 mL for Effluent and 30 mL for Influent
with elevated PQLs of 10 mg/L and 83.3 mg/L, respectively.

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KK. Finding: The laboratory is not using control charts to determine the acceptance criterion of
the LFB.

Requirement: Plot the percent recoveries on a control chart for laboratory evaluation. Ref:
Standard Methods, 2540 A-2015 (5).

Comment: The laboratory is buying a commercially prepared standard which includes a
certified concentration range. They were using that range for the acceptance criterion.

Reporting

LL. Finding for Immediate Response: The laboratory is not certified for the method currently in
use.

Requirement: Municipal and Industrial Laboratories shall obtain Certification for Parameter
Methods used to generate data that will be reported to the State in accordance with the rules
of this Section. Ref: 15A NCAC 02H .0804 (a). Please respond with the corrective actions
taken to prevent further recurrence of this Finding.

Comment: The laboratory has been analyzing regular level TRC samples at the Halifax
Hatchery location (Permit # WQ0006058) without certification using a Hach Pocket
Colorimeter. A Notice of Finding for Immediate Response (NOFIR) was issued. The laboratory
has agreed to obtain certification for TRC, SM 4500 Cl G-2011 (Aqueous) within 30 days (May
29, 2023).

Comment: On May 26, 2023, the laboratory obtained certification for TRC, SM 4500 Cl G-
2011 (Aqueous). However, the laboratory is reminded that all results prior to this date need to
be reported to the Washington Regional Office as uncertified.

MM. Finding: Data qualifiers from the contract laboratory reports are not being transferred to the
DMR.

Requirement: Reported data associated with quality control failures, improper sample
collection, holding time exceedances, or improper preservation shall be qualified as such. Ref:
15A NCAC 02H .0805 (e) (5).

Comment: For the February 22, 2023 Perdue Foods Oil & Grease Effluent result, the contract
lab qualified it with S- spike data not within established limits. The laboratory did not transfer
the qualifier to the DMR.

IV. PAPER TRAIL INVESTIGATION:

The paper trail consisted of comparing original records (e.g., laboratory benchsheets, logbooks, etc.) and
contract laboratory reports to DMRs submitted to the North Carolina Division of Water Resources. Data
were reviewed for Perdue Foods - Lewiston (NPDES permit # NC0028835) for April 2022, September
2022 and February 2023. The following errors were noted:

Date Parameter Location
Value on
Benchsheet
*Contract
Laboratory Data
Value on DMR

2/2/23 BOD Effluent 8.60 mg/L 8.68 mg/L
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2/3/23 BOD Effluent 8.38 mg/L 8.87 mg/L
2/22/23 Oil & Grease Effluent *“s” No qualifier

V. CONCLUSIONS:

Correcting the above-cited Findings and implementing the Recommendations 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: Tom Halvosa Date: May 10, 2023
Report reviewed by: Michael Cumbus Date: May 11, 2023

Certificate Number:245
Effective Date:1/1/2023
Expiration Date:12/31/2023
Lab Name:Perdue Foods - Lewiston
Address:3539 Governors Road
Lewiston Woodville, NC 27849
North Carolina Wastewater/Groundwater Laboratory Certification
Certified Parameters Listing
Date of Last Amendment:3/31/2023
The above named laboratory, having duly met the requirements of 15A NCAC 2H.0800, is hereby certified for the measurement of the parameters listed below.
CERTIFIED PARAMETERS
INORGANIC
BACTERIA - COLIFORM FECAL
IDEXX Colilert ®18 (MPN) (Aqueous)
BOD
SM 5210 B-2016 (Aqueous)
CHLORINE, TOTAL RESIDUAL
SM 4500 Cl E-2011 (Aqueous)
CONDUCTIVITY
SM 2510 B-2011 (Aqueous)
DISSOLVED OXYGEN
SM 4500 O H-2016 (Aqueous)
NITROGEN, AMMONIA
SM 4500 NH3 C-2011 (Aqueous)
OIL & GREASE
EPA 1664 Rev. B (Aqueous)
pH
SM 4500 H+B-2011 (Aqueous)
RESIDUE, DISSOLVED 180 C
SM 2540 C-2015 (Aqueous)
RESIDUE, SUSPENDED
SM 2540 D-2015 (Aqueous)
RESIDUE, TOTAL
SM 2540 B-2015 (Aqueous)
TEMPERATURE
SM 2550 B-2010 (Aqueous)
This certification requires maintance of an acceptable quality assurance program, use of approved methodology, and satisfactory performance on evaluation samples. Laboratories are subject to civil penalties and/or decertification for infractions
as set forth in 15A NCAC 2H.0807.