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HomeMy WebLinkAbout#690_2022_0922_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 November 9, 2022 690 Mr. Steve Walser Lexington WTP 28 West Center St Lexington, NC 27292 Subject: North Carolina Wastewater/Groundwater Laboratory Certification Branch (NC WW/GW LCB) Maintenance Inspection Dear Mr. Walser: Enclosed is a report for the inspection performed on September 22, 2022 by Michael Cumbus. 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, #690 INSPECTION REPORT ROUTING SHEET To be attached to all inspection reports in-house only. Laboratory Cert. #: 690 Laboratory Name: Lexington WTP Date Mailed: Special Mailing Instructions: Michael to email copy to WSRO On-Site Inspection Report LABORATORY NAME: Lexington WTP NPDES PERMIT #: NC0028037 ADDRESS: 2979 Greensboro St Ext Lexington, NC 27295 CERTIFICATE #: 690 DATE OF INSPECTION: September 22, 2022 TYPE OF INSPECTION: Municipal Initial AUDITOR(S): Michael Cumbus LOCAL PERSON(S) CONTACTED: Steve Walser and Tamika Wardlow I. INTRODUCTION: This laboratory was inspected by a representative of the North Carolina Wastewater/Groundwater Laboratory Certification Branch (NC WW/GW LCB) to verify its compliance with the requirements of 15A NCAC 02H .0800 for the analysis of compliance monitoring samples. II. GENERAL COMMENTS: The facility is neat and well organized and has all the equipment necessary to perform the analyses. Staff were forthcoming and responded well to suggestions from the auditor. The laboratory added Total Suspended Residue on September 26, 2017 and was reclassified as a non- Field Municipal laboratory. Prior to this date, the laboratory was classified as a Field Municipal laboratory (Certificate # 5435). The laboratory was last inspected on April 27, 2011. All required Proficiency Testing (PT) Samples have been analyzed for the 2022 PT Calendar Year and the graded results were 100% acceptable. 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 April 15, 2023. Page 2 #690 Lexington WTP 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”. Contracted analyses are performed by Cameron Testing Services, Inc (Certification #654). 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: Multiple instances of write-overs or obliterations were noted, many of which also lacked the date of change and analyst’s initials. B. Finding: The laboratory benchsheet for Total Residual Chlorine (TRC) is lacking required documentation: instrument identification and the time of analysis for the daily check standard. 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: 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: Daily Check Standard analysis date and time. Ref: NC WW/GW LCB Approved Procedure for the Analysis of Total Residual Chlorine (DPD Colorimetric by SM 4500 Cl G- 2011). C. Finding: The laboratory benchsheet for Total Suspended Residue (TSR) 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. Each item shall be recorded each time that samples are analyzed. Ref: 15A NCAC 02H .0805 (a) (7) (F) (xii). Comment: The laboratory benchsheet is lacking units for the weights of the crucible and filter combinations pre- and post-analysis. Page 3 #690 Lexington WTP D. Finding: The laboratory benchsheet for Turbidity is lacking required documentation: the true value of the calibration verification 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: The following must be documented in indelible ink whenever sample analysis is performed: True values of the standards (determined by the manufacturer’s calibration procedure). Ref: NC WW/GW LC Approved Procedure for the Analysis of Turbidity. E. Finding: Some benchsheets reference unapproved methods. 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). Comment: The laboratory benchsheet for TSR lists the method revision year as 2011 instead of 2015, which went into effect September 30, 2021 with the 40 CFR Part 136 Method Update Rule. F. 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 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 traceability log for the filters used in TSR analysis is lacking the Date Opened (in use) and the use of TSR filters is not traceable to the analytical batch in which they are used. Comment: The stock solution used for TRC calibration verification was recorded in the Reagent Quality Control log simply as “Cl std” without noting the chemical compound (potassium permanganate), the concentration (0.891 mg/L) or the vendor name (Ricca). No space was allotted for the date in use. G. Finding: The preparation of standards and reagents are not documented in such a way as to provide traceability from preparation to analysis. 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, Page 4 #690 Lexington WTP 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 Reagent Quality Control Log for the preparation of TRC standards lacks space for the volume of stock standard used, the final volume and solvent used to be recorded. H. Finding: The laboratory is not using control charts to determine the acceptance criterion of the Laboratory Fortified Blank (LFB) for TSR. 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. Ref: Standard Methods 2540 A-2015 (5). Comment: The laboratory is using a commercially prepared standard and is evaluating the results against the true value and the acceptance criterion provided by the manufacturer. I. Finding: The evaluation of the LFB recovery for TSR is 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: the quality control assessments. Ref: 15A NCAC 02H .0805 (g) (2) (O). Comment: Documentation on the laboratory benchsheet does not include the true value and acceptance range for the LFB. In order to establish that the recovery of the LFB meets the criterion, the laboratory must include this information on the benchsheet. J. Finding: The laboratory is not documenting the temperature each time samples are being placed into and removed from the drying oven. Requirement: The date, time and temperature must be documented each time samples are placed into, and removed from, a drying oven. Ref: NC WW/GW LCB Residue Oven Temperature Documentation Policy. Proficiency Testing K. Finding: The laboratory is not documenting PT Sample analyses in the same manner as routine Compliance Samples. Requirement: All PT Sample analyses must be recorded in the daily analysis records as for any Compliance Sample. This serves as the permanent laboratory record. Ref: Proficiency Testing Requirements, February 19, 2020, Revision 5, Section 3.6. Page 5 #690 Lexington WTP Requirement: The laboratory shall retain all records necessary to facilitate historical reconstruction of the analysis and reporting of analytical results for PT Samples. This means the laboratory must have available and retain for five years [pursuant to 15A NCAC 02H .0805 (a) (7) (E) and (g) (1)] all of the raw data, including benchsheets, instrument printouts and calibration data, for all PT Sample analyses and the associated QC analyses conducted by all parameter methods. Ref: Proficiency Testing Requirements, February 19, 2020, Revision 5, Section 4.0. Requirement: The analysis of Proficiency Testing (PT) Samples is designed to evaluate the entire process used to routinely analyze and report Compliance Sample results. PT Samples must be analyzed the same as Compliance Samples. Also, documentation must be made on the same benchsheets used for Compliance Samples. Ref: NC WW/GW LCB Proficiency Testing Samples Analyzed and Documented Same as Compliance Samples Policy. Comment: The laboratory is using the data forms and instruction sheets that accompany the PT samples as the benchsheets for PT sample analysis. PT samples are analyzed on the day that compliance samples are analyzed. If an analysis requires a calibration, that calibration is documented on the laboratory benchsheet for compliance samples. L. 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, however the instructions must be maintained. Ref: Proficiency Testing Requirements, February 19, 2020, Revision 5, Section 3.6. Comment: Dating and initialing the instruction sheet for each prepared PT Sample would satisfy the documentation requirement. QA/QC M. Finding: Rounding off by dropping insignificant digits is not being properly done. Requirement: Round off by dropping digits that are not significant. If the digit 6, 7, 8, or 9 is dropped, increase preceding digit by one unit; if the digit 0, 1, 2, 3, or 4 is dropped, do not alter preceding digit. If the digit 5 is dropped, round off preceding digit to the nearest even number: thus 2.25 becomes 2.2 and 2.35 becomes 2.4. Ref: Standard Methods, 1050 B-2006. (2). Comment: The laboratory benchsheet for May 3, 2022 has Turbidity values of 3.7 NTU and 3.78 NTU with an average of 3.8 NTU recorded. Comment: The laboratory must record when the final digit of the instrument reading is zero, rather than dropping the digit, to ensure that values are properly rounded for rounding and/or averaging. N. Finding: Laboratory temperature-measuring devices (TMD) are not labeled with their respective correction factors. Requirement: Document any correction that applies (e.g., add 0.2 °C, subtract 0.3 °C, or if no correction needed; 0.0 °C) on both the temperature-measuring device and in a format that can be retained for a minimum of five years. Routine temperature measurements must be Page 6 #690 Lexington WTP documented with any applicable correction factor applied. Ref: NC WW/GW LCB Temperature Measuring-Devices used for Laboratory Operations Policy. Comment: The drying oven for TSR was lacking the correction factor of 0.0 °C. O. Finding: The calibration period for the Reference Temperature-Measuring Device used to check other thermometers and/or temperature sensors had expired. Requirement: Reference Temperature-Measuring Devices shall meet National Institute of Standards and Technology (NIST) specifications for accuracy and shall be recalibrated in accordance with the manufacturer's recalibration date. If no recalibration date is given, the Reference Temperature-Measuring Device shall be recalibrated every five years. Ref: 15A NCAC 02H .0805 (a) (7) (N) (i). Comment: The certificate for the laboratory’s Reference TMD listed a calibration date of December 9, 2019 and an expiration date of December 9, 2020. The auditor recommended during the inspection that the analyst inquire about a 5-year calibration. Please submit a copy of a valid calibration certificate with your response. Residue, Total Suspended – Standard Methods, 2540 D-2015 (Aqueous) Comment: The laboratory is analyzing a dry filter blank in addition to the Method Blank as an evaluation of the preparation of the filters used in analyses. A dry filter blank is not required. P. Finding: The samples are not weighed to constant weight. Requirement: Repeat the cycle (drying, cooling, desiccating, and weighing) until the weight change is <0.5 mg. Ref: Standard Methods, 2540 D-2015. (3) (c). Comment: The laboratory is performing a single cycle of drying, cooling, desiccating and weighing. Comment: The laboratory is performing an annual drying study in lieu of multiple cycles of drying, cooling desiccating and weighing. The analyst was informed during the inspection that drying studies are no longer allowed as of January 1, 2021. Q. 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: Data reviewed prior to the inspection showed that the laboratory is using a maximum volume of 250 mL when performing analyses. This volume did not yield any results that met the minimum weight gain required by the analytical method for the months reviewed. R. 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 Page 7 #690 Lexington WTP 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 the results as the calculated value rather than “less than” the adjusted reporting limit. As an example, the laboratory analyzed 250 mL of sample on June 22, 2022 and reported a value of 3.8 mg/L, rather than <10 mg/L. S. Finding: The acceptance criterion for duplicate analyses is frequently exceeded without corrective action being taken. 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). Comment: The laboratory currently has an acceptance criterion of < 10% RPD for the duplicate analyses. Many samples have very low values, which makes meeting the 10% requirement difficult. Recommendation: It is recommended that the laboratory consider a two-tiered system for evaluating duplicate results. As an example, for samples with values less than 5 times the reporting limit (i.e. 12.5 mg/L) a criterion of ± 2.5 mg/L may be more practical, while an acceptance criterion of < 10% RPD might be more practical for samples whose results exceed 12.5 mg/L. Another option would be to use control charts to establish an acceptance criterion. T. Finding: Acceptance criteria have not been established for the daily balance weight checks. 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). U. Finding: The laboratory is not consistently analyzing an 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 (2540 G). 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 did not analyze an LFB during the month of May 2022. Turbidity – Standard Methods, 2130 B-2011 (Aqueous) Comment: The laboratory is analyzing turbidity samples in duplicate. Sample duplicates are not a required quality control element for Field Parameters. Page 8 #690 Lexington WTP V. Finding: The laboratory is performing analyses with an instrument that is not compliant with the certified method. Requirement: Differences in instrument design will cause differences in measured values for turbidity even though the same suspension is used for calibration. To minimize such differences, observe the following design criteria: Light source – Tungsten-filament lamp operated at a color temperature between 2200 and 3000K. Ref: Standard Methods, 2130 B- 2011. (2) (a) . Comment: The laboratory is using a Hach TU5200 for compliance sample analysis. This instrument uses a laser light source instead of a tungsten-filament lamp. The instrument is compliant with Mitchell Method M5271, which is available for certification by the NC WW/GW LCB. Comment: The laboratory has been achieving grades of Acceptable on their PT studies using this instrument, so the impact on data quality is not considered significant. Reporting Recommendation: Since the analyst is not the person entering data into the DMR, it is recommended that the laboratory benchsheets be revised to include a “Reported Value” column. W. Finding: Values less than the established reporting limit are being reported on the DMR for TRC. 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: 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 have a concentration less than the permitted Daily Maximum Limit. The lower reporting limit concentration is equal to the lowest standard concentration. Sample concentrations that are less than the lower reporting limit must be reported as a less-than value. Ref: NC WW/GW LCB Approved Procedure for the Analysis of Total Residual Chlorine (DPD Colorimetric by SM 4500 Cl G- 2011). Comment: The laboratory has verified the manufacturer’s calibration curve down to 10 µg/L. Results less than this value must be reported as <10 µg/L. The laboratory’s current practice is to enter the value from the instrument into the DMR without evaluating the result against the reporting limit. X. Finding: The laboratory does not report results of all tests on the characteristics of the effluent. Requirement: The results of all tests on the characteristics of the effluent, including but not limited to NPDES Permit Monitoring Requirements, shall be reported on monthly report forms. Ref: 15A NCAC 02B .0506 (b) (3) (J). Comment: The laboratory analyzed a Turbidity sample collected May 5, 2022 but no results were entered into the DMR. Y. Finding: Values for pH were reported that exceed the method specified accuracy of 0.1 units. Page 9 #690 Lexington WTP 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). Comment: Per PT Vendor instructions, the PT Sample results should be reported to two decimal places, which is an exception to the requirement for Compliance Samples. Recommendation: The laboratory currently reports pH sample results to two decimal places. It is recommended that the laboratory continue to measure and document sample results on the benchsheet to two decimal places, and to round to the nearest 0.1 S.U. when reporting results on the DMR. Z. Finding: The laboratory is not reporting results of Turbidity analyses to the correct number of decimal places. Requirement: Report turbidity readings as follows: Turbidity Range NTU Report to the Nearest NTU 0-1.0 0.05 1-10 0.1 10-40 1 40-100 5 100-400 10 400-1000 50 >1000 100 Ref: Standard Methods, 2130 B-2011. (5). Comment: Current laboratory practice is to analyze the sample in duplicate and then report the average turbidity of the two readings as calculated. AA. Finding: Data that does not meet all QC requirements is not qualified on the Discharge Monitoring Report (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: Data for TSR is not being qualified when the duplicate acceptance criterion is not met. 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 Lexington WTP (NPDES permit # NC0028037) for January, May and June 2022. The following errors were noted: Page 10 #690 Lexington WTP Date Parameter Location Value on Benchsheet *Contract Laboratory Data Value on DMR 1/11/2022 TSR Effluent 10.0 mg/L 12.6 mg/L 1/11/2022 Zinc Effluent 2 µg/L* 1 µg/L 1/11/2022 Copper Effluent <1 µg/L* 2 µg/L 5/3/2022 Turbidity Effluent 3.81 NTU 3.78 NTU 5/2/20222 Hardness Effluent 34.3 mg/L* 46.52 mg/L 5/2/20222 Hardness Upstream 27.3 mg/L* 36.57 mg/L 6/22/2022 pH Effluent 6.79 S.U. 6.7 S.U. 1. See Finding Z. 2. Date Collected on the Chain of Custody for the contract lab is 5/2/2022. Date on the DMR and on the laboratory benchsheet for in-house analyses is 5/3/2022. 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 Recommendation(s) will help this laboratory to produce quality data and meet Certification requirements. The inspector would like to thank the staff for their assistance during the inspection and data review process. Please respond to all Findings and include supporting documentation, implementation dates and steps taken to prevent recurrence for each corrective action. Report prepared by: Michael Cumbus Date: October 14, 2022 Report reviewed by: Jill Puff Date: October 17, 2022 Certificate Number:690 Effective Date:1/1/2022 Expiration Date:12/31/2022 Lab Name:Lexington WTP Address:2979 Greensboro Street Extension Lexington, NC 27295 North Carolina Wastewater/Groundwater Laboratory Certification Certified Parameters Listing Date of Last Amendment:8/27/2021 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 CHLORINE, TOTAL RESIDUAL SM 4500 Cl G-2011 (Aqueous) pH SM 4500 H+B-2011 (Aqueous) RESIDUE, SUSPENDED SM 2540 D-2015 (Aqueous) TURBIDITY SM 2130 B-2011 (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.