#569_2019_1118_MC_FINAL

11►[+'1-:21x01[9701N21 061: AZT61IkIIi!LOW a4
Laboratory Cert. :
569
Laboratory Name:
Coddle Creek Water Treatment Plant
Inspection Type:
Municipal Maintenance
Inspector Name(s):
Michael Curnbus and Beth Swanson
Inspection Date:
November 18, 2019
Date Forwarded for Initial
December 4, 2019
Review:
Initial Review by:
JMS
Date Initial Review
December 5, 2019
Completed:
❑ Insp. Initial
® Insp. Reg
Cover Letter to use:
❑Insp. No Finding
❑Corrected
❑Insp. CP
❑Insp. Reg. Delay
(to use: rt click, properties, ;heck)
Unit Supervisor/Chemist III:
Beth Swanson
Date Received:
12/10/2019
Date Forwarded to Admin.:
12/16/2019
Date Mailed:
12/17/2019
Special Mailing Instructions:
Michael Email copy to MRO

ROB" COOPER
Ede m, (v el lm,
MICHALL S. REGAN
fl` d'r'fi;lr:y
LINDA CULPEPPE
Environmental Qualiff
December 17, 2019
569
Ms. Tonia L. Shupe
Coddle Creek Water Treatment Plant
P. O. Box 308
Concord, NC 28026
Subject: North Carolina Wastewater/Groundwater Laboratory Certification (NC WW/GW LC)
Maintenance Inspection
Dear Ms. Shupe:
Enclosed is a report for the inspection performed on November 18, 2019 by Michael Cumbus and Beth
Swanson. Where Finding(s) are cited in this report, a response is required. Within thirty days of receipt,
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 2H .0800.
A copy of the laboratory's Certified Parameter List at the time of the audit is attached. This list will 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 wish to obtain an
electronic copy of this report by email or if you have questions or need additional information, please
contact me at [phone] Ext. 259.
Attachment
cc: Michael Cumbus, Dana Satterwhite
Sincerely,
-//
Beth Swanson
Technical Assistance & Compliance Specialist
Division of Water Resources
tf/
North Carolina Department of Environmental Quality ; Division of Water Resources
1623 Mail Service Center I Raleigh. North Carolina 27699-1623
Phone [phone]/Fax [phone]

LABORATORY NAME:
NPDES PERMIT #:
ADDRESS:
CERTIFICATE #:
DATE OF INSPECTION:
TYPE OF INSPECTION
AUDITOR(S):
LOCAL PERSON(S) CONTACTED
I. INTRODUCTION:
Coddle Creek Water Treatment Plant
NC0083119
6935 Davidson Highway
Concord, NC 28026
569
November 18, 2019
Municipal Maintenance
Michael Cumbus and Beth Swanson
Tonia Shupe, Steven Smith and Rebecca Shue
This laboratory was inspected by representatives of the North Carolina Wastewater/Groundwater
Laboratory Certification (NC WW/GW LC) program to verify its compliance with the requirements of
15A NCAC 2H .0800 for the analysis of environmental samples.
II. GENERAL COMMENTS:
The facility is neat and well organized and has all the equipment necessary to perform the
analyses. The equipment appears well maintained. Staff were forthcoming and seemed eager to
adopt necessary changes. Records are well organized and easy to retrieve.
All Proficiency Testing (PT) Samples have been analyzed for the 2019 PT Calendar Year and the
graded results were 100% acceptable.
Contracted analyses are performed by Pace Analytical Services, LLC — Asheville NC (Certification
# 40).
Approved Procedure documents for the analysis of the facility's currently certified Field Parameters
were provided at the time of the inspection.
The laboratory is reminded that any time changes are made to laboratory procedures, the
laboratory must update the QA/SOP documents) and inform relevant staff. Any changes made
in response to the review or to Findings, Recommendations or Comments listed in this report
must be incorporated to insure the method is 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

Page 2
#569 Coddle Creek Water Treatment Plant
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.
The laboratory is also reminded that SOPs 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".
11911ki1/71ki[ei�;1*0111Ia=1ITimg1j6-jLGji7►41►iI=1gk mil zIej a :we]ivilim=1k,IBm"IIm zu
Documentation
Comment: The traceability log does not contain the vendor name. However, all Certificates of
Analysis are kept in an accompanying notebook, thus maintaining a traceable link from analysis to
vendor via lot numbers.
Recommendation: It is recommended that the laboratory note on the refrigerator temperature logs
that the correction factor is applied prior to recording the value on the log.
EO
10
QA/QC
C
Finding: The laboratory benchsheet for pH is 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. Ref: 15 NCAC 2H .0805 (a) (7) (F) (xii).
Requirement: The following must be documented in indelible ink whenever sample
analysis is performed: units of measure. Ref: NC WW/GW LC Approved Procedure for the
Analysis of pH.
Comment: The laboratory benchsheet is lacking units of measure in the meter calibration
section and data entry section.
Finding: The laboratory needs to increase the traceability documentation of standards and
reagents prepared in the laboratory.
Requirement: Adherence to manufacturer expiration dates is required.
Chemicals/reagents/consumables exceeding the expiration date can no longer be
considered reliable. If the expiration is only listed as a month and year (with no specific day
of the month), the last day of the month will be considered the actual date of expiration.
Monitor materials for changes in appearance and consistency. Any changes may indicate
potential contamination and the item should be discarded, even if the expiration date is not
exceeded. If no expiration date is given, the laboratory must have a policy for assigning an
expiration date. If no date received or expiration date can be determined, the item should
be discarded. Ref: NC WW/GW LC Policy.
Comment: The laboratory standard preparation log is lacking dates of expiration for
prepared reagents and standards.
Finding: Data that does not meet all QC requirements is not qualified on the Discharge
Monitoring Report.

Page 3
#569 Coddle Creek Water Treatment Plant
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 21-1.0805 (e) (5).
Comment: The laboratory was not transcribing data qualifiers from the contract laboratory
reports to the DMR. The following errors were noted: an effluent sample collected on
January 8, 2019 for TKN/Total Nitrogen and an effluent sample collected on April 2, 2019
for Fluoride, both analyzed by Pace Analytical Laboratories, were lacking qualifiers on the
corresponding DMR that had been included in the client report.
Comment: The laboratory is not qualifying Suspended Residue data when the minimum
reporting limit is not achieved due to reduced sample volume.
Proficiencv Testing
D. 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 Procedure documents shall be available for inspection by the State Laboratory.
Ref: 15A NCAC 21-1.0805 (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
laboratory must also be able to explain when PT Sample analysis is not possible for certain
methods and provide a description of what the laboratory is doing in lieu of Proficiency
Testing. This shall be detailed in the plan. 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, October 29, 2018, Revision 3.
E. Finding: The laboratory is not documenting the preparation of PT Samples.
Requirement: PT Samples received as ampules are diluted according to the Accredited
PT Sample Provider's instructions. It is important to remember to document the preparation
of PT Samples in a traceable log or other traceable format. The diluted PT Sample then
becomes a routine Compliance Sample and is added to a routine sample batch for
analysis. No documentation is needed for whole volume PT Samples which require no
preparation (e.g., pH), but it is recommended that the instructions be maintained. Ref:
Proficiency Testing Requirements, October 29, 2018, Revision 3.
Comment: Dating and initialing the instruction sheet for each prepared PT Sample would
satisfy the documentation requirement.

Page 4
#569 Coddle Creek Water Treatment Plant
Chlorine, Total Residual.— Standard Methods, 4500 Cl G-2011
Recommendation: It is recommended that the laboratory change the concentration of the
standards used in the calibration curves. Currently the laboratory is using standards of: 0, 15, 50,
100, 200, and 400 pg/L residual chlorine. Replacing one of the higher standards with one closer to
the laboratory's reporting limit (e.g. 15, 25, 50, 200, and 400 pg/L) would put more weight on the
lower end of the curve, where compliance sample concentrations typically fall.
F. Finding for Immediate Response: The annual Laboratory -generated Calibration curve did
not pass the individual standard recovery criteria for instrument A.
Requirement: Back calculate the concentration of each calibration point. For standards
< 50 pg/L, the back -calculated value and standard true value must agree within ± 25%.
For standards >_ 50 pg/L, the back -calculated value and standard true value must agree
within ± 10%. Ref: NC UWV/GW LC Approved Procedure for the Analysis of Total Residual
Chlorine (DPD Colorimetric). Please submit a passing calibration curve for meter A
with the report reply.
Comment: The laboratory has two Mach DR 5000 meters designated as "A" and "B", with
calibration curves last established May 22, 2019. The laboratory did not back calculate
the standards to evaluate whether the recoveries met acceptance criteria before using
them for compliance purposes. Each curve was evaluated the day following the
inspection and it was discovered that the 15 pg/L standard recovery of 128% exceeded
the acceptance criteria of ± 25%. A finding for immediate response was issued November
20, 2019 stating that instrument A could not be used for compliance monitoring due to
an unacceptable curve. The laboratory responded on November 20, 2019 that instrument
"A" was now out of service and would remain so until all acceptance criteria had been met.
G. Finding: The laboratory is not back -calculating the concentration of each calibration point
used in the Laboratory -Generated calibration curve.
Requirement: Back calculate the concentration of each calibration point. For standards
< 50 pg/L, the back -calculated value and standard true value must agree within ± 25%.
For standards z 50 pg/L, the back -calculated value and standard true value must agree
within ± 10%. Ref: NC WW/GW LC Approved Procedure for the Analysis of Total Residual
Chlorine (DPD Colorimetric).
H. Finding: The laboratory is not analyzing a Reagent Blank with the calibration curve.
Requirement: If preparing standards, analyzing a PT Sample or analyzing diluted samples,
a Reagent Blank is required. Ref: NC WW/GW LC Approved Procedure for the Analysis of
Total Residual Chlorine (DPD Colorimetric)
Comment: The laboratory had prepared a blank, but incorporated it into the calibration
curve as a separate point. A second Reagent Blank was not analyzed.
Recommendation: It is recommended that, in the future, the laboratory not include the
calibration blank absorbance as a point in the calibration curve.
I. Finding: The laboratory is not reporting data to the lower reporting limit.
Requirement: For all calibration options, the range of standard concentrations must
bracket the permitted discharge limit concentration, the range of sample concentrations
to be analyzed and anticipated PT Sample concentrations. One of the standards must

Page 5
#569 Coddle Creek Water Treatment Plant
have a concentration less than the permitted Daily Maximum Limit. The lower reporting limit
concentration is equal to the lowest standard concentration. Ref: NC WW/GW LC
Approved Procedure for the DPD Colorimetric Analysis of Total Residual Chlorine
Comment: The concentration of the lowest standard in the current calibration curve is 15
pg/L. However, data from November 5, 2019 was recorded as having a final value of <17
pg/L, which is the discharge permit limit, instead of <15 pg/L, which is the laboratory
reporting limit. While the reported value is technically correct, it does not meet our
requirements for establishing a reporting limit based on the concentration of the lowest
calibration standard.
.— �li . . — 1 .0 1 I 4e 11 r ,:1'
J. Finding: The laboratory benchsheet for pH is lacking required documentation: sample
identification.
Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data
shall be traceable to the associated sample analyses and shall consist of: sample
identification. Ref: 15A NCAC 02H .0805 (a) (7) (F) (ix).
Comment: The laboratory benchsheet did not clearly indicate which buffers were being
used for the daily calibration, and which buffer was being used as calibration verification.
Laboratory personnel indicated that the 4 S.U. and 7 S.U. buffers are being used to
calibrate the pH meter, and the 10 S.U. buffer is being used as a calibration verification.
K. Finding: Values are sometimes reported that exceed the method specified accuracy of 0.1
units.
Requirement: By careful use of a laboratory pH meter with good electrodes, a precision of
±0.02 unit and an accuracy of ±0.05 unit can be achieved. However, ± 0.1 pH unit
represents the limit of accuracy under normal conditions, especially for measurement of
water and poorly buffered solutions. For this reason, report pH values to the nearest 0.1 pH
unit. Ref: Standard Methods, 4500 H+ B-2011. (6).
Requirement: Values must be reported in tenths (0.1). Ref: NC WW/GW LC Approved
Procedure for the Analysis of pH.
Turbidi — Standard Methods, 2130 B-2011
Recommendation: It is recommended that the laboratory analyze the calibration verification
standard prior to sample analysis, rather than at the end of sample analysis.
L. Finding: The laboratory is not evaluating and documenting the percent recovery of the
calibration verification 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 2H .0805 (a) (7) (A).

Page 6
#569 Coddle Creek Water Treatment Plant
Requirement: If quality control results fall outside established limits or show an
analytical problem, the laboratory shall identify the Root Cause of the failure. The
problem shall be resolved through corrective action, the corrective action process
documented, and any samples involved shall be reanalyzed, if possible. If the sample
cannot be reanalyzed, or if the quality control results continue to fall outside established
limits or show an analytical problem, the results shall be qualified as such. Ref: 15A
NCAC 02H .0805 (a) (7) (B).
Residue, Suspended — Standard Methods, 2540 D-2011
Comment: Suspended Residue is considered a method -defined parameter per the definition in the
Code of Federal Regulations, Part 136.6, Section (a) (5). This means that per Section (b) (3), the
method may not be modified.
Comment: Effective January 1, 2021, NC WW/GW LC will no longer allow drying studies or dry
filter blanks to substitute for drying and weighing to a constant weight. Prior to filtering samples, all
filters will have to be washed and dried to a constant weight (within 0.5 mg of the prior weight). All
filters after filtering samples will also have to be dried and weighed to a constant weight (within 0.5
mg of the prior weight).
M. Finding: The laboratory is not evaluating and documenting the Relative Percent Difference
(RPD) of duplicate analyses 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 2H .0805 (a) (7) (A).
Requirement: If quality control results fall outside established limits or show an
analytical problem, the laboratory shall identify the Root Cause of the failure. The
problem shall be resolved through corrective action, the corrective action process
documented, and any samples involved shall be reanalyzed, if possible. If the sample
cannot be reanalyzed, or if the quality control results continue to fall outside established
limits or show an analytical problem, the results shall be qualified as such. Ref: 15A
NCAC 02H .0805 (a) (7) (B).
N. 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 complete
filtration takes more than 10 min, increase filter diameter or decrease sample volume. Ref:
Standard Methods, 2540 D-2011 (3) (b).
Comment: The laboratory is currently analyzing 500 mL of sample.
IV. PAPER TRAIL INVESTIGATION:

Page 7
#569 Coddle Creek Water Treatment Plant
The paper trail consisted of comparing original records (e.g., laboratory benchsheets, logbooks,
etc.) and contract lab reports to Discharge Monitoring Reports (DMRs) submitted to the North
Carolina Division of Water Resources. Data were reviewed for Coddle Creek Water Treatment
Plant (NPDES permit # NC0083119) for September 2018, January and April 2019. The
following errors were noted:
Value on
Benchsheet
Date
Parameter
Location
Value on DMR
*Contract Lab
Data
1/08/2019
Nitrogen,
Effluent
*No Value
< 0.02 mg/L
Ammonia
Reported
4/02/2019
Effluent
*< 0.1 mg/L
0.71 mg/L
Ammonn,
* The Ammonia values are results from the NO2+NO3 contract lab data, incorrectly reported in the
Ammonia cell. NO2+NO3 data was correctly incorporated into the Total Nitrogen calculation for the
purposes of the DMR.
To avoid questions of legality, it is recommended that you contact the appropriate Regional
Office for guidance as to whether an amended DMR(s) will be required. A copy of this report
will be made available to the Regional Office.
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: Michael Cumbus Date: December 4, 2019
Report reviewed by: Jason Smith Date: December 5, 2019