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HomeMy WebLinkAbout#559_2023_0315_MC_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 559 Ms. Gosia Kraska K & W Laboratories 1121 Hwy. 24/27 W Midland, NC 28107- Subject: North Carolina Wastewater/Groundwater Laboratory Certification Branch (NC WW/GW LCB) Maintenance Inspection Dear Ms. Kraska: Enclosed is a report for the inspection performed on March 15 and 24, 2023 by Michael Cumbus, Beth Swanson, Anna Ostendorff, Jill Puff and Jason Smith. 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, Michael Cumbus, #559 On-Site Inspection Report LABORATORY NAME: K & W Laboratories ADDRESS: 1121 Hwy. 24/27 W Midland, NC 28107 CERTIFICATE #: 559 DATE OF INSPECTION: March 15, 2023 and March 24, 2023 TYPE OF INSPECTION: Commercial Maintenance AUDITOR(S): Michael Cumbus, Beth Swanson, Anna Ostendorff, Jill Puff and Jason Smith LOCAL PERSON(S) CONTACTED: Gosia Kraska, Wioleta Montgomery, Szymon Kraska and Kayla Wainer 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: This inspection was performed on two separate days. The laboratory began implementing corrective actions between the two visits. The laboratory is to be commended for their efforts to improve the quality of their data and processes. The facility is very neat and well organized and has all the equipment necessary to perform the analyses. Staff were knowledgeable and forthcoming and responded well to suggestions from the auditor. All required Proficiency Testing (PT) Samples for the 2023 PT Calendar Year have been analyzed, but remedial PT Samples are pending for Unacceptable PT Sample Results. Any time changes are made to laboratory procedures, Quality Assurance (QA) and/or Standard Operating Procedure (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 April 30, 2024. 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”. Page 2 #559 K & W Laboratories 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 Meritech Inc. (Certification #165) and Pace Analytical Services LLC – Huntersville NC (Certification #12). III. FINDINGS, REQUIREMENTS, COMMENTS AND RECOMMENDATIONS: Documentation Recommendation: The laboratory may find it helpful to include a cover sheet with instrument data packages that includes quality control assessments or other documentation requirements. 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 the error correction was lacking the date that the change was made. B. Finding: The 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). Comment: This Finding applies to the following parameter methods, though this may not be an exhaustive list: • Bacteria – Coliform Fecal – Standard Methods, 9222 D-2015 (MF) (Aqueous) • Bacteria – E. Coli – IDEXX Colilert 18® (MPN) (Aqueous) • BOD/CBOD – Standard Methods, 5210 B-2016 (Aqueous) • Chloride – Standard Methods, 4500 Cl- C-2011 (Aqueous) • Conductivity – Standard Methods, 2510 B-2011 (Aqueous) • Nitrogen, Ammonia – Standard Methods, 4500 NH3 D-2011 (Aqueous) • Nitrogen, NO3 + NO2 – Standard Methods, 4500 NO3- F-2016 (Aqueous) • Nitrogen, Total Kjeldahl (TKN) – Standard Methods, 4500 Norg C-2011 (Standard Methods, 4500 NH3 D-2011) (Aqueous) • Oil & Grease – EPA Method 1664, Rev. B (Aqueous) • Phosphorus, Total – Standard Methods, 4500 P F-2011 (Aqueous) • Residue, Dissolved 180°C – Standard Methods, 2540 C-2015 (Aqueous) C. Finding: Some benchsheets, digestion logs and report summaries reference unapproved methods and/or do not fully reference the approved methods. Page 3 #559 K & W Laboratories Requirement: Analytical methods, sample preservation, sample containers, and sample holding times shall conform to the requirements found in: 40 CFR Part 136 and 40 CFR Part 503. Ref: 15A NCAC 02H .0805 (a) (1) (A). 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: Client reports reviewed prior to the inspection lacked the method revision year. Comment: The laboratory benchsheet for TKN lists a method revision year of 1997. Comment: The laboratory benchsheets for Chloride and Fluoride are lacking the method revision year. Comment: The laboratory benchsheet for BOD/CBOD lists a method revision year of 2011. Comment: The laboratory benchsheet for Total Dissolved Residue (TDR) lists a method revision year of 2011. Comment: The sample digestion log for TKN is lacking the method or SOP reference. Recommendation: This list may not be exhaustive. It is recommended that the laboratory review all benchsheets to ensure that the method references match the laboratory’s Certified Parameters Listing (CPL). D. Finding: The volume of sample analyzed for TKN is not consistently documented on the laboratory benchsheet. Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall be traceable to the associated sample analyses and shall consist of: the volume of sample analyzed, where applicable. Each item shall be recorded each time samples are analyzed. Ref: 15A NCAC 02H .0805 (a) (7) (F) (xi). Comment: The laboratory benchsheet includes a space for the sample volume in the determinative step of the method, but this is not consistently filled out. E. Finding: The volume of 10N NaOH added to TKN standards and samples is not documented. Requirement: Add a sufficient volume of 10N NaOH solution (1 mL usually is sufficient) to raise pH above 11. If the presence of silver or mercury is possible, use NaOH/EDTA solution in place of NaOH solution. If it is necessary to add more than 1 mL of either NaOH or NaOH/EDTA solution, note volume used, because it is required for subsequent calculations. Ref: Standard Methods, 4500 NH3 D-2011. (4) (b). Requirement: Measurement of samples: Dilute if necessary to bring NH3-N concentration to within calibration curve range. Place 100 mL sample in 150-mL beaker and follow procedure in ¶ b above. Record volume of 10N NaOH added. Ref: Standard Methods, 4500 NH3 D-2011. (4) (e). F. Finding: The laboratory benchsheet is lacking required documentation: all manual calculations and the quality control assessments. Page 4 #559 K & W Laboratories Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall be traceable to the associated sample analyses and shall consist of: all manual calculations and all quality control assessments. Each item shall be recorded each time that samples are analyzed. Ref: 15A NCAC 02H .0805 (a) (7) (F) (xiv) and (xv). Comment: The laboratory benchsheet for Nitrate + Nitrite Nitrogen lacks the calculation and the acceptance criterion for the column efficiency. G. Finding: The laboratory benchsheets are lacking the acceptance criteria for the quality control assessments or other acknowledgement that the criteria are being met. 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. Ref: 15A NCAC 02H .0805 (a) (7) (F) (xv). Comment: The laboratory benchsheets for Fluoride, Nitrate Nitrogen, Metals and Total Phosphorus are lacking acceptance criteria for the QC assessments. Comment: The laboratory benchsheet for Total Phosphorus is lacking evaluation of the back- calculated calibration curve standards. Comment: The metals analyst stated that an acceptance criterion for 'Std5', which is the lower reporting limit standard, has been set at a recovery of ±20%. However, the SOP and benchsheet do not state any criterion. Comment: The Metals and COD benchsheets do not include the blank acceptance criterion. Comment: The laboratory benchsheets for Total Dissolved Residue and Total Suspended Residue lack an acknowledgement that the constant weight requirement has been met. Comment: The laboratory benchsheets for Total Dissolved Residue and Total Suspended Residue lack an acknowledgement that the Method Blank weight gain is < 0.5mg/L. Comment: The laboratory benchsheet for TKN lacks the acceptance criterion for the LFB. Comment: The benchsheet for Fecal Coliform and E. Coli lack the acceptance criteria for sample duplicates. H. Finding: QC assessments for Field Parameter analyses are not being documented. 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. Ref: 15A NCAC 02H .0805 (g) (2) (O). Comment: The recovery of standards and RPD of duplicates for Turbidity are documented, but there are no acceptance criteria listed for each QC item, nor acknowledgment that they meet acceptance criteria. There is no blank criterion listed on the benchsheet. Comment: The Conductivity benchsheet lacks an acceptance criterion for the daily check standard. Comment: The pH benchsheet is lacking the evaluation of the check standard buffer. Page 5 #559 K & W Laboratories I. Finding: Units of measure are not consistently documented on the laboratory benchsheet. 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: 15A NCAC 02H .0805 (g) (2) (L). Comment: The benchsheet for Turbidity is lacking units for the “Reading” and “True Value” rows. J. Finding: The laboratory benchsheets for Turbidity and Chloride are 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. Each item shall be recorded each time that samples are analyzed. Ref: 15A NCAC 02H .0805 (a) (7) (F) (iii). 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. Analyses shall conform to methodologies found in Subparagraph (a)(1) of this Rule. Ref: 15A NCAC 02H .0805 (g) (2) (C). K. Finding: The time that samples are put into the fecal water bath is not recorded. Requirement: The date and time that samples are placed into and removed from ovens, water baths, incubators and other equipment shall be documented if a time limit is required by the method. Ref: 15A NCAC 02H .0805 (a) (7) (F). Requirement: Place all prepared cultures in the water bath within 30 min after filtration. Ref: Standard Methods, 9222 D-2015. (3) (d). Requirement: Place prepared dishes in waterproof plastic bags, remove as much air as possible, seal, invert, and submerge Petri dishes in water bath; incubate for 24 ± 2 h at 44.5 ± 0.2 °C. Ref: Standard Methods, 9222 D-2015. (3) (d). Comment: Neither the required incubation time of 24 ± 2 hours, nor the 30-minute Requirement above can be verified without all required times being documented. Proficiency Testing L. Finding: The laboratory does not have a documented plan for PT procedures. 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. Page 6 #559 K & W Laboratories 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 occasionally analyzes PT Samples in duplicate, or will repeat the analysis on a different day. Comment: The laboratory uses previous PT study samples for their LFB in some analyses. This is standard practice and is not considered additional QC, but rather a commercially prepared standard. Quality Assurance / Quality Control (QA/QC) Recommendation: It is recommended that the laboratory incorporate reading of SOPs into the training section of the QA Manual, each time a revision is made to the SOP and analytical method. N. Finding: The laboratory is not analyzing a standard at the same concentration as the minimum reporting level concentration each day samples are analyzed. Requirement: With each analytical batch, analyze a reagent-water sample spiked at MRL and ensure that it meets MRL acceptance criteria (generally ±50%). If not, re-analyze the entire batch or flag results for all samples in the batch. If the MRL is biased high, nondetect (ND) samples can be reported with flags if the method or regulation allows. Ref: Standard Methods, 4020 B-2014. (9). Requirement: With each analytical batch, analyze a reagent-water sample spiked at MRL and ensure that it meets MRL acceptance criteria (generally ±50%). If not, re-analyze the entire batch or flag results for all samples in the batch. Ref: Standard Methods, 5020 B-2017. (9). Comment: This Finding applies to the following parameter methods: • Nitrogen, Ammonia – Standard Methods, 4500 NH3 D-2011 (Aqueous) • Nitrogen, Total Kjeldahl – Standard Methods, 4500 Norg C-2011 (Standard Methods, 4500 NH3 D-2011) (Aqueous) • COD – Standard Methods, 5220 B-2011 (Aqueous) • Phosphorus, Total – Standard Methods, 4500 P F-2011 (Aqueous) Page 7 #559 K & W Laboratories O. Finding: Data that does not meet all QC requirements is not always qualified on the client report. 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: The laboratory failed to qualify Nitrate + Nitrite Nitrogen data analyzed on July 26, 2022. The efficiency of the reduction column was 86%, which is outside the acceptable range of 90-110%. The second LFM/LFMD pair exhibited low recovery bias. Neither QC failure was noted on the client report, but was noted on the benchsheet. P. Finding: The laboratory is not calculating the reduction column efficiency for Nitrate + Nitrite Nitrogen. Requirement: Calculate reduction efficiency as follows: Efficiency = (NO3- -N response/NO2- -N response) * 100 Ref: Standard Methods, 4500 NO3- F-2016. (6). Comment: The laboratory is using an acceptance criterion of 90-110% recovery of the nitrite standard, rather than calculating the efficiency. Q. Finding: SOPs have not been fully developed or 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, 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 laboratory SOP for Nitrate Nitrogen does not mention the determination and subtraction of Nitrite Nitrogen. Since the laboratory does not hold certification for Nitrite, the laboratory is not required to maintain a separate SOP document for Nitrite. At a minimum, the Nitrate Nitrogen SOP must include either a reference to another SOP document or include the procedure for determining the Nitrite concentration and calculations for determining the final Nitrate concentration. R. Finding: The laboratory is evaluating the average recovery of the LFM and LFM duplicate, instead of evaluating both the LFM and LFM duplicate separately for accuracy. Page 8 #559 K & W Laboratories Requirement: Evaluate LFM results for percent recovery; if they are not within control limits, then take corrective action to rectify the matrix effect, use another method, use the method of standard addition, or flag the data if reported. See method for specific LFM-acceptance criteria until the laboratory develops statistically valid, laboratory-specific performance criteria. Ref: Standard Methods, 4020 B-2014. (7). Requirement: Evaluate LFM duplicate results for precision and accuracy (precision alone for duplicate samples). Ref: Standard Methods, 4020 B-2014. (8). Comment: This Finding applies to the following parameter methods: • Phosphorus, Total – Standard Methods, 4500 P F-2011 (Aqueous) • Nitrogen, NO3 + NO2 – Standard Methods, 4500 NO3- F-2016 (Aqueous) S. Finding: The laboratory is not properly determining the MDL for metals analyses. Requirement: At least once every thirteen months, recalculate MDLs and MDLb from the collected spiked samples and method blank results using the equations in section 2. 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. (4) (a). Comment: The laboratory does not determine a blank MDL (MDLb) value and compare it to the MDL spike (MDLs) value. T. Finding: Thermometers in the bacteria incubators are not verified against a Reference Temperature-Measuring Device at least every three months. 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). U. Finding: For chemicals/reagents/consumables that do not have an expiration date, the laboratory has not established a policy for assigning expiration dates. Requirement: If the expiration date 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 or consistency. Any changes may indicate potential contamination; therefore, the item must not be used, 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 neither a date received nor an expiration date can be determined, the item must not be used. Ref: NC WW/GW LCB Chemical, Reagent, Standard and Consumable Expiration Dates Policy. Comment: Multiple instances were noted where reagents have not been assigned an expiration date and SOPs lack guidance for assigning one. The laboratory needs to establish a policy for assigning expiration dates and review each chemical to ensure that all chemicals and reagents have been assigned an expiration date. V. Finding: The laboratory is not analyzing Oil & Grease samples in duplicate. Requirement: Except where otherwise specified in an analytical method, laboratories shall analyze five percent of all samples in duplicate to document precision. Laboratories analyzing Page 9 #559 K & W Laboratories 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). W. Finding: An inconsistency was noted between the SOP and laboratory practice as follows: the laboratory prepares the COD calibration curve with a standard at a lower concentration than the range listed in the SOP. 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 laboratory has calibrated the COD instrument with a series of standards from 10 to 500 mg/L. The SOP states that the lowest concentration standard is 20 mg/L. Comment: Since there are often changes in technology or options within a particular method that are not covered in the published method reference, the laboratory SOP is the prescriptive reference document that describes a laboratory’s analytical procedure in detail. This document is intended to be the reference for analysts performing the specified test procedure. X. Finding: The laboratory has not established an acceptance criterion for evaluation of the standard at the lowest reporting concentration. 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). Y. Finding: The laboratory has not established an acceptance criterion for precision and accuracy when a duplicate LFB is analyzed. 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: This Finding applies to Nitrate+Nitrite Nitrogen by Standard Methods, 4500 NO3 - F-2016. Z. Finding: The laboratory is not using control charts to determine the acceptance criterion of the LFB for Total Dissolved Residue (TDR) and Total Suspended Residue (TSR). Page 10 #559 K & W Laboratories Requirement: Plot the percent recoveries on a control chart for laboratory evaluation. Ref: Standard Methods 2540 A-2015. (5). Alkalinity – Standard Methods, 2320 B-2011 (Aqueous) Comment: The laboratory has not analyzed any compliance samples within the past year. Bacteria – Coliform Fecal – Standard Methods, 9222 D-2015 (MF) (Aqueous) Bacteria – E. Coli – IDEXX Colilert 18® (MPN) (Aqueous) AA. Finding: The laboratory reports the arithmetic mean (average) of duplicate results. Requirement: Any average for Fecal Coliform is to be calculated as a geometric mean. Ref: Directions for Completing Monthly Discharge Monitoring Reports, Section II, (8). Requirement: Weekly Average (concentration limit): The arithmetic mean of all "daily discharges" of a pollutant measured during the calendar week. In the case of fecal coliform or other bacterial parameters or indicators, the geometric mean of such discharges. Ref: Part II Standard Conditions for NPDES Permits, Section A. Comment: In order to enable clients to correctly report bacterial results, the laboratory must either calculate the geometric mean for any compliance samples performed in duplicate, or include both results on the client report. Bacteria – E. Coli – IDEXX Colilert 18® (MPN) (Aqueous) BB. Finding: The laboratory is not documenting the verification of the absence of residual chlorine in samples. Requirement: Sample preservation shall be verified and documented. Ref: 15A NCAC 02H .0805 (a) (7) (M). Bacteria – Coliform Fecal – Standard Methods, 9222 D-2015 (MF) (Aqueous) CC. Finding: The laboratory does not have an acceptance criterion for the consumable materials use test. Requirement: Before a new lot of consumable materials are used for the Fecal Coliform MF method, those materials must be tested and compared to those currently in use to ensure they are reliable. Consumable materials included in this requirement are: membrane filters and/or pads (often packaged together) and media. It is recommended that only one consumable be tested at a time. At a minimum, make single analyses on five positive samples that will yield 20-60 colonies for both the current lot and the new lot. There are two options for determining acceptance of results: Option 1: Follow the acceptance criteria described in Standard Methods 9020 B. (5) (f) (2) (a) and (b). Option 2: Compare the average colony count of each five-sample set and evaluate against your routine sample duplicate acceptance criterion. Ref: NC WW/GW LCB Testing of Consumable Materials for Fecal Coliform MF Method Policy. DD. Finding: Culture positive plates are not analyzed weekly for purchased ready-to-use media. Page 11 #559 K & W Laboratories Requirement: For each lot of medium received, each laboratory-prepared batch of medium, and each lot of commercially prepared medium, verify appropriate response by testing with known positive and negative control cultures for the organism(s) under test. See Table 9020:VI for examples of test cultures. Record results. Ref: Standard Methods, 9020 B-2015. (9) (b). Requirement: A culture positive must be analyzed with each batch of prepared media and once per week for purchased ready-to-use media. The sample volume used must yield a plate showing individual colonies with proper morphology (e.g., color, shape, size, surface appearance). Ref: NC WW/GW LCB Coliform Membrane Filter Culture Positive Policy. EE. Finding: Colony verification is not properly performed. Requirement: Verify positives monthly by picking at least 10 blue colonies from one positive sample using lauryl tryptose broth and EC broth as directed in Section 9221E.1. Adjust counts based on percent verification. Ref: Standard Methods, 9020 B-2015. (10) (b) (2). Requirement: On a monthly basis, at least ten blue colonies from the medium must be verified using Lauryl Tryptose Broth and EC broth, followed by count adjustment based on these results; and representative non-blue colonies should be verified using Lauryl Tryptose Broth. Where possible, verifications should be done from randomized sample sources. Ref: Code of Federal Regulations, Title 40, Part 136; Federal Register Vol. 86, No. 95, May 19, 2021; Table II, Footnote 30. Comment: The laboratory is currently using multiple samples instead of a single sample. FF. Finding: The laboratory is not autoclaving the filtration units after each use. Requirement: Membrane filtration equipment: Before initial use, assemble filtration units and check for leaks. Discard units if chipped or inside surfaces are scratched. Units that leak should be repaired accordingly or discarded. Replace damaged screens on stainless steel units. Wash and rinse filtration assemblies thoroughly after use, wrap in nontoxic paper or foil, and sterilize via autoclave or dry heat oven. When measuring sample volumes using funnels with volumetric graduation marks, initially check the marks’ accuracy using a Class A graduated cylinder or volumetric pipet. Record results. For presterilized single-use funnels, check one per lot or a set percentage (e.g., 1 to 4%) to confirm the accuracy of volumetric graduation mark. Ref: Standard Methods, 9020 B-2015. (4) (k). Comment: The laboratory is currently sterilizing the filtration units on a monthly basis, with one unit used per week. Batches of samples are bracketed with dilution water sterility checks. Dilution water sterility checks associated with data examined all had results of 0 cfu. COD – Standard Methods, 5220 D-2011 (Aqueous) Comment: The laboratory is verifying the thermometer built into the hot block, as well as monitoring the temperature each day of use with a thermometer in a COD vial filled with glycerin. The built in thermometer has a correction factor of -10°C, which exceeds the stated accuracy requirements. Recommendation: To avoid confusion, it is recommended that the laboratory cover the temperature display on the hot block (e.g., with tape or a sticker), or note on the hot block that the built in thermometer is not to be used to monitor the temperature of the hot block and remove the correction factor for the built in thermometer. Page 12 #559 K & W Laboratories GG. Finding: The laboratory is improperly analyzing low range (i.e., below 100 mg/L) samples. Requirement: For COD values between 100 and 900 mg/L, increase in Cr3+ in the 600-nm region is determined. Higher values can be obtained by sample dilution. COD values of 90 mg/L or less can be determined by following the decrease in Cr2O72- at 420 nm. The corresponding generation of Cr3+ gives a small absorption increase at 420 nm, but this is compensated for in the calibration procedure. Ref: Standard Methods 5220 D-2011. (1) (a). Comment: COD is considered a method-defined parameter per the definition in the Code of Federal Regulations, Part 136.6, Section (a) (5). This means the method must be followed as written. Comment: The laboratory is currently using a single calibration curve at 600 nm with a working range of 10-500 mg/L. Concentrations below 100mg/L must be analyzed at 420 nm. HH. Finding: The laboratory is not preparing the LFM correctly. 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. Comment: The laboratory is preparing the LFM/LFMD for COD analysis with a spike volume that is 10% of the total sample volume. II. 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. Conductivity – Standard Methods, 2510 B-2011 (Aqueous) Comment: The laboratory analyzed a sample duplicate on October 21, 2022. Duplicates are not a requirement for Field Parameters. The laboratory reports the average of the two readings on the client report. JJ. Finding: The conductivity cell (i.e., probe) is not rinsed with sample prior to analysis. 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: Thoroughly rinse conductivity cell with one or more portions of sample prior to sample measurement. Ref: NC WW/GW LCB Approved Procedure for the Analysis of Specific Conductance (Conductivity). Page 13 #559 K & W Laboratories Metals – EPA Method 200.7, Rev. 4.4, 1994 (Aqueous) KK. Finding: The laboratory’s acceptance criterion for the Quality Control Standard (QCS) does not meet the method requirements. Requirement: To verify the calibration standards the determined mean concentrations from three analyses of the QCS must be within ±5% of the stated values. If the calibration standard cannot be verified, performance of the determinative step of the method is unacceptable. Ref: EPA Method 200.7, Rev. 4.4 (1994), Section 9.2.3. Comment: The laboratory is currently using an acceptance criterion of ± 10% for the second source QCS (which the laboratory calls ICV). Nitrogen, Ammonia – Standard Methods, 4500 NH3 D-2011 (Aqueous) Nitrogen, Total Kjeldahl – Standard Methods, 4500 Norg C-2011 (Standard Methods, 4500 NH3 D-2011) (Aqueous) Comment: The laboratory benchsheet has a space for the instrument reading and a separate space for the reported results. The laboratory records the reading for the Method Blank (MB) as less than, followed by the displayed value (e.g., < 0.0461 mg/L) in the space for instrument reading, but does not utilize the space for reported results. The less than symbol is not appropriate in the space for the instrument reading since it is not part of the actual instrument reading. Documentation of the evaluation of the MB (e.g., < 0.05 mg/L) would be appropriate in the space for reported results. Nitrogen, Total Kjeldahl – Standard Methods, 4500 Norg C-2011 (Standard Methods, 4500 NH3 D-2011) (Aqueous) Recommendation: Ammonia-nitrogen standard solutions do not undergo the chemical conversion during the digestion step that organically bound nitrogen standards do. In order to effectively monitor the digestion process, it is recommended that the laboratory use an organically bound nitrogen as the source for the matrix spike and matrix spike duplicate. The laboratory currently uses an organically bound nitrogen source for the LFB, purchased from an approved PT vendor. Alternatively, glutamic acid (GA) may be used. 1.0504 g GA/L = 100 ppm Nitrogen stock solution. LL. Finding: The laboratory is not certified for the method currently in use. Requirement: Commercial Laboratories shall obtain Certification for Parameter Methods used to generate data that will be reported by the client to the State in accordance with the rules of this Section. Ref: 15A NCAC 02H .0804 (a). Comment: At the time of the previous inspection, the laboratory was certified for the Macro- Kjeldahl method (Standard Methods 4500 Norg B-2011). Subsequently, the laboratory introduced a block digestor, smaller reagent volumes and smaller sample volumes, which falls under the Semi Micro-Kjeldahl method (Standard Methods 4500 Norg C-2011). The determinative method, Standard Methods 4500 NH3 D-2011, is correct, and the SOP was updated to reflect the digestion method being used, though the method reference on the SOP and benchsheets is incorrect. No record of a request to substitute the methods was found. The laboratory must submit an Amendment to Certification form, as well as an updated SOP as part of the response to this Finding. Page 14 #559 K & W Laboratories Comment: The laboratory benchsheet lists the method reference for the Macro-Kjeldahl method. When the laboratory amends their certification to reflect the Semi-Micro Kjeldahl method, the laboratory benchsheets must be updated to reflect the change. MM. Finding: The laboratory is not distilling the digested TKN samples prior to analysis by the determinative method. Requirement: Manual digestion (4500 Norg B-2011 or C-2011) and distillation (4500 NH3 B- 2011) or gas diffusion followed by any of the following: Electrode (4500 NH3 D-2011). Ref: Code of Federal Regulations, Title 40, Part 136; Federal Register Vol. 86, No. 95, May 19, 2021; Table IB. NN. Finding: The laboratory is calibrating the instrument with a different volume of sample than the volume used for compliance sample analyses. Requirement: Electrometer calibration: place 100 mL of each standard in a 150-mL beaker. Immerse electrode in standard of lowest concentration and mix with a magnetic stirrer. Ref: Standard Methods, 4500 NH3 D-2011. (4) (b). Requirement: Measurement of samples: Dilute if necessary to bring NH3-N concentration to within calibration curve range. Place 100 mL sample in a 150-mL beaker and follow procedure in ¶b above. Ref: Standard Methods, 4500 NH3 D-2011. (4) (e). Comment: Current laboratory practice is to use 100 mL of ammonium chloride standard solutions to calibrate the instrument, and 50 mL of digestate. This may result in air entrainment or inadequate submerging of the electrode when stirring a 50 mL volume. Nitrogen, NO3 + NO2 – Standard Methods, 4500 NO3- F-2016 (Aqueous) OO. Finding: The laboratory is not filtering turbid samples prior to analysis. Requirement: Interferences: Suspended matter may restrict sample flow in the column, so filter turbid samples (see 4500-NO3- .A.1). Ref: Standard Methods, 4500 NO3- F-2016. (1) (b). Requirement: Treatment of sample: 1) Turbidity removal – Filter turbid samples (see 4500- NO3-.A.1). Ref: Standard Methods, 4500 NO3- F-2016. (4) (b). Comment: The laboratory is diluting samples by a factor of 10 if they are turbid. Comment: Filtering of the Method Blank and LFB are required when samples are filtered. PP. Finding: The laboratory is not checking samples for residual chlorine. Requirement: Residual chlorine can oxidize the Cd column, reducing its efficiency, so check samples for residual chlorine (see DPD methods in Section 4500-Cl) and, if necessary, remove by adding Na2SO3 solution (Section 4500-NH3.B.3d). Ref: Standard Methods, 4500 NO3- F-2016. (1) (b). Comment: The laboratory is reminded that if dechlorinating agents are added to samples, then the Method Blank and LFB must contain those reagents as well. Page 15 #559 K & W Laboratories QQ. Finding: The laboratory is not documenting that the sample pH is between 5 and 9 S.U. prior to sample analysis. This is considered pertinent information. 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: If sample pH is < 5 or > 9, adjust to between 5 and 9 with either conc HCl or conc NH4OH. Ref: Standard Methods, 4500 NO3- F-2016. (4). Oil & Grease – EPA Method 1664, Rev. B (Aqueous) Comment: The laboratory was previously using a SpeedVap III for the removal of the solvent from the sample extract, but has since ceased using this equipment and instead is allowing the hexane to evaporate at room temperature. This is an allowable modification to the method per Section 1.7.1.2 and does not require any comparability study, provided all performance criteria in the method are met. RR. Finding: The laboratory is not using the correct reporting limit when 1000 mL of sample is analyzed. Requirement: For HEM and SGT-HEM in this method, the method detection limit (MDL) is 1.4 mg/L and the minimum level of quantitation (ML) is 5.0 mg/L (Reference 16.3). Ref: EPA Method 1664, Rev. B, Section 1.6. Comment: The laboratory is using a reporting limit of 5.6 mg/L when 1000 mL of sample is analyzed. Comment: When a full liter of sample is not available for analysis, the laboratory must adjust the reporting limit by dividing the method-defined reporting limit of 5.0 mg/L by the volume of sample in liters. Example: if a sample volume of 900 mL (0.9 L) is analyzed, the reporting limit would be 5.0/0.9 (i.e., 5.6 mg/L). SS. Finding: The laboratory’s acceptance criterion for the LFM exceeds the method-specified acceptance criterion. Requirement: Compare the percent recovery of the HEM or SGT-HEM with the corresponding QC acceptance criteria in Table 1. Ref: EPA Method 1664, Rev. B, Section 9.3.4. Requirement: Acceptance Criterion: Matrix Spike/Matrix Spike Duplicate: HEM Recovery Limit (%): 78 – 114. Ref: EPA Method 1664, Rev. B, Section 17.0, Table 1. Comment: The laboratory is using an acceptance criterion of 75-125% recovery for the LFM. No exceedances of the method defined limit were noted when reviewing data. TT. Finding: The laboratory is not using the correct extraction solvent. Requirement: The extraction solvent must be n-hexane (85% minimum purity, 99.0% min. saturated C6 isomers, residue less than 1 mg/L – see Section 7.3). Alternate extraction solvents or co-solvents including methanol, acetone and others that react with or introduce the target pollutant into the sample are not allowed. Ref: EPA Method 1664, Rev. B, Section 1.7.2.1. Page 16 #559 K & W Laboratories Comment: The laboratory is currently using “Hexanes” as the solvent. This is a separate solvent from n-Hexane and as such, is not permitted by the method. pH – Standard Methods, 4500 H+ B-2011 (Aqueous) Comment: The laboratory benchsheet states in a footnote that the calibration check buffer “should be within ± 0.1 units of the buffer’s true value”. Use of the word “should” is not appropriate when describing requirements and needs to be replaced with “must”. UU. Finding: The laboratory is not analyzing a check standard buffer after calibration and prior to sample analysis. 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: Instruments are to be calibrated according to the manufacturer’s calibration procedure prior to analysis of samples each day compliance monitoring is performed. Calibration must include at least two buffers. The meter calibration must be verified with a third standard buffer solution (i.e., check buffer) prior to sample analysis. Ref: NC WW/GW LCB Approved Procedure for the Analysis of pH. VV. Finding: The laboratory is not correctly documenting the true value of the buffers used to calibrate the instrument. Requirement: Laboratory procedures shall comply with Subparagraph (a)(1) of this Rule. Ref: 15A NCAC 02H .0805 (g) (4). Requirement: The following must be documented in indelible ink whenever sample analysis is performed: true values of buffers used for calibration. Ref: NC WW/GW LCB Approved Procedure for the Analysis of pH. Comment: The laboratory benchsheet includes column headings for the calibration which are labeled as “Calibration Buffer Check”. Since the word “Check” is commonly used for calibration verification, it may lead to confusion regarding whether or not the instrument was calibrated prior to sample analysis. Recommendation: It is recommended that the word “Check” be removed from any columns that are not documenting the calibration verification. Phosphorus, Total – Standard Methods, 4500 P F-2011 (Aqueous) WW. Finding: The laboratory is using an acceptance criterion of ±15% recovery for the second- source standard. Requirement: Verify the initial calibration by analyzing a standard prepared from a different stock standard than that used to create the calibration curve; its concentration should be near the midpoint of the calibration range. The analytical results for this second-source mid-range standard must be within 10% of its true value. Ref: Standard Methods, 4020 B-2014. (1) (b). XX. Finding: A calibration blank is not analyzed after calibration and prior to sample analysis. Page 17 #559 K & W Laboratories Requirement: A calibration blank and calibration verification standard shall be analyzed prior to sample analysis, after every tenth sample, and at the end of each sample group, unless otherwise specified by the method, to check for carryover and calibration drift. Ref: 15A NCAC 02H .0805 (a) (7) (H). Comment: The calibration blank is only analyzed as part of the calibration curve and then after 10 samples and at the end of the sample group. Residue, Total Dissolved 180°C – Standard Methods, 2540 C-2015 (Aqueous) Residue, Total Suspended – Standard Methods, 2540 D-2015 (Aqueous) Comment: The laboratory is fortifying samples. LFMs and LFMDs are not a required QC element for residue parameters. Recommendation: The lab currently has a 90-110% criterion for sample duplicates, regardless of value. It is recommended that the laboratory establish a two-tier duplicate acceptance criterion based on sample concentration. Residue, Total Dissolved 180°C – Standard Methods, 2540 C-2015 (Aqueous) YY. Finding: The laboratory is not using glass-fiber filters to perform the analysis. Requirement: Glass-fiber filter disks, 22 to 125 mm dia, ≤ 2-µm nominal pore size without organic binder. Ref: Standard Methods, 2540 C-2015 (2) (a). Comment: The laboratory is currently using sterile membrane filters with a pore size of 0.45 µm, the same filters used in bacteria analyses. ZZ. Finding: The laboratory does not always utilize at least 30 mL volume of water for the blank. Requirement: Using the same containers and glassware normally in contact with samples, put 30 mL of DI water through the sample filter and proceed through the entire analytical process. Acceptance criterion is <0.5 mg weight gain. Ref: NC WW/GW LCB Method Blank Analysis Requirement for Suspended, Dissolved and Total Residue Policy. Comment: The laboratory occasionally uses 25 mL of water for the blank. The intent of the policy is that at least 30 mL must be used. Turbidity – Standard Methods, 2130 B-2011 (Aqueous) AAA. Finding: The laboratory is diluting samples above 40 NTU. Requirement: Avoid dilution whenever possible. Ref: Standard Methods, 2130 B-2011. (4) (a). Comment: Dilution of samples above 40 NTU is only a requirement when certified for method EPA 180.1. When using Standard Methods 2130 B-2011, samples within the instrument's calibrated measurement range shall not be diluted. BBB. Finding: The laboratory benchsheet does not include documentation of daily instrument calibration. Page 18 #559 K & W Laboratories Requirement: A record of instrument calibration or calibration verification shall be documented and available for inspection upon request. Ref: 15A NCAC 02H .0805 (g) (3). Comment: The benchsheet includes meter readback results for the 0.02, 0.10, 10 and 1000 NTU standards, but does not include an acknowledgement that the meter was calibrated prior to the measurements or what standards are used for calibration. Comment: The benchsheet states that instrument calibration is performed every 3 months, however the analyst states that calibration is performed every day. Reporting CCC. Finding For Immediate Response: The laboratory is analyzing samples and reporting data for Nitrite Nitrogen without North Carolina Wastewater/Groundwater Laboratory Certification. Requirement: Commercial Laboratories shall obtain Certification for Parameter Methods used to generate data that will be reported by the client to the State in accordance with the rules of this Section. Ref: 15A NCAC 02H .0804 (a). Comment: During the paper trail portion of the audit, it was noted that some client reports contained results for Nitrite Nitrogen, as well as Nitrate Nitrogen and Nitrate + Nitrite Nitrogen. The laboratory currently holds certification for Nitrate + Nitrite Nitrogen by SM 4500 NO3- F-2016 (Aqueous) and Nitrate Nitrogen by subtraction [(SM 4500 NO3- F -2016) – (SM 4500 NO2- B-2011)]. The NC WW/GW LCB does not require additional certification for the Nitrite Nitrogen portion of the analysis to report Nitrate Nitrogen using this Parameter Method. However, to report the Nitrite Nitrogen result separately as a certified value, certification of a Nitrite Nitrogen Parameter Method is required. The laboratory agreed to immediately cease reporting Nitrite Nitrogen. A Notice of Finding for Immediate Response was issued and returned to the auditor on March 31, 2023. No further response is necessary for this Finding. IV. PAPER TRAIL INVESTIGATION: The paper trail consisted of comparing original records (e.g., laboratory benchsheets, logbooks, etc.) to client reports. Ammonia, Chloride, Total Phosphorus and Nitrate data were reviewed for Reed Gold Mine (permit # WQ0006946) from July 13, 2022 and November 8, 2022. BOD and CBOD data were reviewed for Reed Gold Mine from November 8, 2022 and for Carolina Septic Services from May 19, 2022. TDS data were reviewed for Reed Gold Mine from November 8, 2022. TSS data were reviewed for Leonard Stogner (NPDES permit #NC0029246) from August 3, 2022 and October 5, 2022. E. Coli. data were reviewed for NC DEQ/DWR from October 21 and 24, 2022. TKN data were reviewed for Reed Gold Mine from November 8, 2022 and for Leonard Stogner from August 3, 2022. Data for Metals were reviewed for Leonard Stogner from November 8, 2022 and for Imperial Brown from November 11, 2022. The following error was noted: Sample IDs for Reed Gold Mine (collected November 8, 2022) were incorrectly listed on the benchsheet as 221118-16, 221118-17, 221118-18 and 221118-19, rather than 221108-16, 221108-17, 221108-18, and 221108-19. Analytical results were correctly transcribed to the client report. 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 Page 19 #559 K & W Laboratories include supporting documentation, implementation dates and steps taken to prevent recurrence for each corrective action. Report prepared by: Michael Cumbus Date: April 3, 2023 Report reviewed by: Jason Smith Date: April 6, 2023 Certificate Number:559 Effective Date:1/1/2022 Expiration Date:12/31/2022 Lab Name:K & W Laboratories Address:1121 Hwy. 24/27 W Midland, NC 28107- North Carolina Wastewater/Groundwater Laboratory Certification Certified Parameters Listing Date of Last Amendment:10/12/2022 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 ALKALINITY SM 2320 B-2011 (Aqueous) BACTERIA - COLIFORM FECAL SM 9222 D-2015 (MF) (Aqueous) BACTERIA - COLIFORM TOTAL SM 9222 B-2015 (MF) (Aqueous) BACTERIA - E. coli IDEXX Colilert-18® (MPN) (Aqueous) BOD SM 5210 B-2016 (Aqueous) CBOD SM 5210 B-2016 (Aqueous) CHLORIDE SM 4500 Clˉ C-2011 (Aqueous) CHLORINE, TOTAL RESIDUAL SM 4500 Cl G-2011 (Aqueous) COD SM 5220 D-2011 (Aqueous) CONDUCTIVITY SM 2510 B-2011 (Aqueous) DISSOLVED OXYGEN SM 4500 O G-2016 (Aqueous) FLUORIDE SM 4500 Fˉ C-2011 (Aqueous) NITROGEN, AMMONIA SM 4500 NH3 D-2011 (Aqueous) NITROGEN, NITRATE (NO3 + NO2 SM 4500-NO3ˉ F-2016) - (NO2 SM 4500-NO2ˉ B-2011) (Aqueous) NITROGEN, NO3 + NO2 SM 4500 NO3ˉ F-2016 (Aqueous) NITROGEN, TOTAL KJELDAHL SM 4500 Norg B-2011 (SM 4500 NH3 D-2011) (Aqueous) OIL & GREASE EPA 1664 Rev. B (Aqueous) pH SM 4500 H+B-2011 (Aqueous) PHOSPHORUS, TOTAL SM 4500 P F-2011 (Aqueous) RESIDUE, DISSOLVED 180 C SM 2540 C-2015 (Aqueous) RESIDUE, SETTLEABLE SM 2540 F-2015 (Aqueous) RESIDUE, SUSPENDED SM 2540 D-2015 (Aqueous) TEMPERATURE SM 2550 B-2010 (Aqueous) TURBIDITY SM 2130 B-2011 (Aqueous) METAL ARSENIC EPA 200.7, Rev. 4.4, 1994 (Aqueous) BORON EPA 200.7, Rev. 4.4, 1994 (Aqueous) CADMIUM EPA 200.7, Rev. 4.4, 1994 (Aqueous) CHROMIUM TOTAL EPA 200.7, Rev. 4.4, 1994 (Aqueous) COPPER EPA 200.7, Rev. 4.4, 1994 (Aqueous) IRON EPA 200.7, Rev. 4.4, 1994 (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. Certificate Number:559 Effective Date:1/1/2022 Expiration Date:12/31/2022 Lab Name:K & W Laboratories Address:1121 Hwy. 24/27 W Midland, NC 28107- North Carolina Wastewater/Groundwater Laboratory Certification Certified Parameters Listing Date of Last Amendment:10/12/2022 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 LEAD EPA 200.7, Rev. 4.4, 1994 (Aqueous) MOLYBDENUM EPA 200.7, Rev. 4.4, 1994 (Aqueous) NICKEL EPA 200.7, Rev. 4.4, 1994 (Aqueous) SELENIUM EPA 200.7, Rev. 4.4, 1994 (Aqueous) SILVER EPA 200.7, Rev. 4.4, 1994 (Aqueous) THALLIUM EPA 200.7, Rev. 4.4, 1994 (Aqueous) ZINC EPA 200.7, Rev. 4.4, 1994 (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.