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Home My WebLink About#137 2010-final INSPECTION REPORT ROUTING SHEET To be attached to all inspection reports in-house only. Laboratory Cert. #: 137 Laboratory Name: Big Buffalo Creek WWTP Inspection Type: Municipal Maintenance Inspector Name(s): Jeffrey R. Adams Inspection Date: June 24, 2010 Date Report Completed: July 6, 2010 Date Forwarded to Reviewer: July 9, 2010 Reviewed by: Tonja Springer Date Review Completed: July 13, 2010 Cover Letter to use: Insp. Initial X Insp. Reg. Insp. No Finding Insp. CP Unit Supervisor: Dana Satterwhite Date Received: July 21, 2010 Date Forwarded to Alberta: August 11, 2010 Date Mailed: August 11, 2010 _____________________________________________________________________ On-Site Inspection Report LABORATORY NAME: Big Buffalo Creek WWTP NPDES PERMIT # NC0048879 ADDRESS: 1900 Old Reedy Creek Road Cary, NC 27513 CERTIFICATE #: 137 DATE OF INSPECTION: June 24, 2010 TYPE OF INSPECTION: Municipal Maintenance AUDITOR(S): Jeffrey R. Adams LOCAL PERSON(S) CONTACTED: Scott Siletzky and Dale Deaton I. INTRODUCTION: This laboratory was inspected to verify its compliance with the requirements of 15A NCAC 2H .0800 for the analysis of environmental samples. II. GENERAL COMMENTS: The laboratory was clean and well organized. The facility has all the equipment necessary to perform the analyses. Performance testing samples have been analyzed for all certified parameters for the 2009 proficiency testing calendar year and the graded results were 100% acceptable. Records were maintained and well organized, however, some quality control procedures need to be implemented. The laboratory was presented a packet containing policy changes and requirements during the inspection and these policies were reviewed with the laboratory personnel. Findings A, C, D, J, and K are new policies that have been implemented by our program since the last inspection. III. FINDINGS, REQUIREMENTS, COMMENTS AND RECOMMENDATIONS: Standard Operating Procedures (SOPs) A. Finding: Standard Operating Procedures (SOPs) have not been developed and/or updated for all of the parameters included on the laboratory’s certificate attachment. Requirement: Each laboratory shall develop and maintain a document outlining the analytical quality control practices used for the parameters included in their certification. Supporting records shall be maintained as evidence that these practices are being effectively carried out. Ref: 15A NCAC 2H .0805 (a) (7). Requirement: The laboratory must have an updated Quality Control/Standard Operating Procedures document for the parameters included on the certif icate attachment by February 1, 2011. This must be submitted for review upon completion. A written response is required. Page 2 #137 Big Buffalo Creek WWTP Recommendation: It is recommended that the SOPs be reviewed for accuracy on an annual basis. SOPs must be updated any time a change in procedure is made. It is also recommended that a revision and/or review history with pertinent dates and a brief description of the change(s) made be documented in each SOP. Chemicals and Reagents B. Finding: The laboratory needs to increase the documentation of purchased materials and reagents, as well as, documentation of standards and reagents prepared in the laboratory. Requirement: All chemicals, reagents, standards and consumables used by the laboratory must have the following information documented: 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: North Carolina Wastewater/Groundwater Laboratory Certification Policy. Ammonia – Standard Methods, 18th Edition, 4500 NH3 F COD – Standard Methods, 18th Edition, 5220 D Cyanide – Standard Methods, 18th Edition, 4500 CN E Metals – Standard Methods, 18th Edition, 3111 B Metals – Standard Methods, 18th Edition, 3113 B C. Finding: The laboratory is not analyzing a mid-range standard and blank after every ten samples analyzed and at the end of the run. Requirement: The calibration blank and calibration verification standard (mid-range) must be analyzed initially (i.e., prior to sample analysis), after every tenth sample and at the end of each sample group to check for carry over and calibration drift. If either fall outside established quality control acceptance criteria, corrective action must be taken (e.g., repeating sample determinations since the last acceptable calibration verification, repeating the initial calibration, etc.). Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy based upon Standard Methods, 20th Edition, 1020 B. (10) (c), 3020 B. (2) (b), and 4020 B. (2). Comment: The calibration verification standard is prepared from the calibration stock standard solution. D. Finding: The laboratory is not analyzing matrix spikes. Requirement: Unless the referenced method states a greater frequency, spike 5% of samples on a monthly basis. Laboratories analyzing less than 20 samples per month must analyze at least one matrix spike each month samples are analyzed. Prepare the matrix spike from a reference source different from that used for calibration unless otherwise stated in the method. If matrix spike results are out of control, the results must be qualified or the laboratory must take corrective action to rectify the effect, use another method, or employ the method of standard additions. When the method of choice specifies matrix spike performance acceptance criteria for accuracy, and the laboratory chooses to develop statistically valid, laboratory-specific limits, the laboratory- Page 3 #137 Big Buffalo Creek WWTP generated limits cannot be less stringent than the criteria stated in the approved method. Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy. (See attached document titled Matrix Spiking Policy and Technical Assistance for guidance) BOD – Standard Methods, 18th Edition, 5210 B CBOD – Standard Methods, 18th Edition, 5210 B Comment: On several occasions the blanks exceeded the maximum acceptable values of 0.20 mg/L (e.g., 1.4 and 1.6 mg/L BOD). BOD Negative and positive blanks can occur when poor laboratory hygiene practices are being used, e.g., nutrient buildup in dilution water carboys, poor DO meter and probe air calibration, and not properly rinsing the DO probe between samples. The laboratory should review its maintenance and analyses protocol to eliminate these types of errors. The data was being qualified on the Discharge Monitoring Reports (DMRs), as required, when these errors occurred. Recommendation: The de-ionized water bottle being used for probe storage and air calibration exhibited algae growth, possibly affecting the air calibration of the meter. It is recommended that the water bottle be changed at least weekly and that lab personnel consult the manufacturer’s instructions on probe storage and maintenance. The water bottle was changed during the inspection. Comment: If the membrane is coated with oxygen-consuming (e.g., bacteria) or oxygen-evolving organisms (e.g., algae), erroneous readings may occur. Ref: YSI Operators Manual pg. (7) (4.5) (2). YSI 1/07. Comment: The laboratory is not aging the dilution water. It is recommended that the dilution water be aged in an incubator overnight prior to adding nutrients. Aging water may improve blanks. Do not add nutrients to water until ready to use, and no more than 24 hours prior to use. Conductivity – Standard Methods 18th Edition, 2510 B Dissolved Oxygen – Standard Methods 18th Edition, 4500 O G pH – Standard Methods 18th Edition, 4500 H+ B E. Finding: The laboratory is not posting NIST temperature sensor corrections on the Conductivity, DO and pH meters. Requirement: All thermometers must meet National Institute of Standards and Technology (NIST) specifications for accuracy or be checked, at a minimum annually, against a NIST traceable thermometer and proper corrections made. Ref: 15A NCAC 2H .0805 (a) (7) (O). Comment: Document any correction that applies (even if zero) on both the temperature sensor and on a separate sheet to be filed to ensure accurate data is recorded and maintained according to the required record retention schedules. Conductivity – Standard Methods 18th Edition, 2510 B F. Finding: The Automatic Temperature Compensator (ATC) has not been verified. Requirement: The ATC must be verified annually (i.e., every twelve months) by analyzing a conductivity standard at 25°C (the temperature that conductivity values are compensated to) and a temperature(s) that bracket the temperature ranges of the samples to be analyzed. This may require the analysis of a third temperature reading that is >25°C. Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy. Page 4 #137 Big Buffalo Creek WWTP Ammonia Nitrogen – Standard Methods, 18th Edition, 4500 NH3 F G. Finding: The laboratory is not recording the volume of 10N NaOH added. Requirement: Record volume of 10N NaOH added in excess of 1 ml. Ref: Standard Methods, 18th Edition, 4500-NH3 F. (4) (e). Fecal Coliform (MF) – Standard Methods, 18th Edition, 9222 D H. Finding: No comparison test is conducted before a new lot of media and filters are put into use. Requirement: When a new lot of culture medium, membrane filters, pads or a new source of reagent-grade water is to be used, make comparison tests of the current lot in use (reference lot) against the new lot (test lot). Ref: Standard Methods, 18th Edition Method 9020 (B) (4) (e). (See attached document titled Testing of Consumable Materials for Fecal Coliform MF Method). Recommendation: It is recommended that the comparison tests be performed with a culture positive sample that will yield the desired 20 to 60 colonies. The culture positive sample should be analyzed the day prior to the comparison testing to determine the appropriate dilution to yield 20 – 60 colonies COD – Standard Methods, 18th Edition, 5220 D Metals – Standard Methods, 18th Edition, 3111 B Metals – Standard Methods, 18th Edition, 3113 B Recommendation: It is recommended that the laboratory rotate the position of samples, blanks and quality control samples in the block digester during COD and metals digestions. Random placement will help to identify when optimal performance is not achieved in an individual sample well. It is also recommended that the laboratory implement a temperature grid check of the block digester by alternating the well location of the thermometer each time samples are digested. This will document heating uniformity and consistency of all sample wells in the block. Total Suspended Solids – Standard Methods 18th Edition, 2540 D I. Finding: A minimum dried residue weight gain of 1 mg is used to determine the reporting limit. 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 minutes increase filter diameter or decrease sample volume. Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy based upon Standard Methods, 20th and 21st Editions, 2540 D. (3) (b). Comment: For example, if 100 mL sample is analyzed, and less than 2.5 mg of dried residue is obtained, the value reported would be <25 mg/L. Comment: Since the publication of the Code of Federal Regulations, Title 40, Part 136; Federal Register Vol. 72, No. 47, March 12, 2007, there is no longer an approved method that allows for a 1 mg weight gain. Currently, the minimum weight gain allowed is 2.5 mg. In instances where the weight gain is less than the required 2.5 mg, the value must be reported as less than the appropriate value based upon the volume used. For example, if 500 mL of sample is analyzed Page 5 #137 Big Buffalo Creek WWTP and < 2.5 mg of dried residue is obtained, the value reported would be < 5 mg/L. The minimum reporting value is now established at 2.5 mg/L based upon a sample volume used of 1000 mL. J. Finding: Occasionally, duplicate analyses exceeded the laboratory’s control limits of 20% relative percent difference (RPD), and the data is not being qualified on the DMR. Requirement: When quality control (QC) failures occur, the laboratory must attempt to determine the source of the problem and must apply corrective action. If data qualifiers are used to qualify samples not meeting QC requirements, the data may not be useable for the intended purposes. A notation must be made on the Discharge Monitoring Report (DMR) form, in the comment section, when any required sample quality control does not meet specified criteria, and another sample cannot be obtained. Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy based upon Standard Methods, 20th Edition, 1020 B. (14). Total Solids – Standard Methods, 18th Edition, 2540 B K. Finding: The laboratory is using an incorrect reporting limit. Requirement: Choose sample volume to yield between 2.5 and 200 mg dried residue. To obtain the required residue yield, successive aliquots of samples may be added to the same dish after evaporation or adjust reporting level based upon the weight gain and sample volume used. For example, if 100 mL sample is analyzed, and less than 2.5 mg of dried residue is obtained, the value reported would be <25 mg/L. The minimum reporting value is established at 2.5 mg/L based upon a sample volume used of 1000 mL. Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy based upon Standard Methods, 20th and 21st Editions, 2540 C. (3) (d) and 2540 B. (3) (b). IV. PAPER TRAIL INVESTIGATION: The paper trail consisted of comparing benchsheets and contract lab reports to Discharge Monitoring Reports (DMRs) submitted to the North Carolina Division of Water Quality. Data were reviewed for the Big Buffalo Creek Wastewater Treatment Plant (NPDES permit #NC0024147) for February, March and April, 2010. No transcription errors were detected. The laboratory appears to be doing a good job transcribing data. V. CONCLUSIONS: Correcting the above-cited findings and implementing the recommendations will help this lab to produce quality data and meet certification requirements. The inspector would like to thank the staff for its assistance during the inspection and data review process. Please respond to all findings. Report prepared by: Jeffrey R. Adams Date: July 6, 2010 Report reviewed by: Tonja Springer Date: July 13, 2010 NC DENR/DWQ LABORATORY CERTIFICATION Testing of Consumable Materials for Fecal Coliform MF Method Standard Methods requires that before a new lot of consumable materials are used for the Fecal Coliform MF method, those materials be tested to ensure they are reliable. North Carolina policy requires the testing of the following consumable materials before they can be used for sample analyses: membrane filters and/or pads (often packaged together) and media. Test only one consumable at a time. REQUIREMENT: It is required that when a new lot of culture medium, pads, or membrane filters is to be used, a comparison of the current lot in use (reference lot) against the new lot (test lot), be made. As a minimum, make single analyses on five positive samples. Ref: Standard Methods, 18th Edition - Method 9020 B.3d. (page 9-7). The following is provided as guidance in performing the required testing. Let’s say you got a new batch of membrane filters in. We will call the currently used filters lot #1 and the new filters lot #2. 1. Select a culture positive sample. What you want is something that will yield 20-60 colonies when a reasonable sample volume is filtered. This may be a stream sample or a sample taken somewhere within the waste treatment plant. If the concentration is high enough that greater than 60 colonies are obtained when 1 mL is filtered then the solution is too strong and must be diluted. Any time a sample is diluted be sure it is done with the BUFFERED dilution water used for rinsing the funnels. 2. Test the culture positive to determine the appropriate volume to use. When collecting the culture positive sample do not think about it as a sample. You do not have to be concerned with a sterile sample bottle or 6 hour hold time. Collect enough sample so that you have plenty to work with, probably more than your normal fecal bottle holds. Set a series of dilutions using the currently used materials, in this example filter lot #1. Do not use the materials you want to prove are OK at this point. All you are trying to do is to determine the volume of sample that will yield 20-60 colonies. Put the rest of the sample in the refrigerator. For example: Volume used Colonies obtained on lot #1 filters 50 ml TNTC 25 ml 138 10 ml 50 5 ml 22 1 ml 4 Based on this preliminary testing it appears that a 10 ml volume would probably be appropriate to use and will yield the desired 20-60 colonies. Remember when you do the actual consumable test, the culture positive sample will be 24 hours old and the results you obtain may be lower than the initial results yielded, but not so significantly lower as to change your dilution choice. It is better to have your initial results on the high side of the 20-60 range for this reason. In this example the 5 ml volume would probably be too low and would likely yield less than 20 colonies the next day. 3. Perform the consumable test Once you determine the appropriate volume, in this case 10 mls, take the remaining culture positive sample from the refrigerator, bring to room temperature and set five 10 ml plates with the currently used filters, lot #1, and five 10 ml plates with the new filters, lot #2. 4. Determine acceptability of new material For example: Lot #1-current filters Colonies obtained on lot #1 filters 10 ml 48 10ml 45 10 ml 50 10 ml 44 10 ml 43 Average: 46 Lot #2-new filters Colonies obtained on lot #2 filters 10 ml 40 10ml 45 10 ml 38 10 ml 46 10 ml 37 Average: 41 When determining the acceptability of the new material, compare the average of the five replicates for lot #1 to the average of the five replicates for lot #2; that is 46 vs. 41 colonies. The recommended acceptance criteria would be your current acceptance criteria used for your Fecal Coliform duplicates. If the test and reference materials check within what you have determined is acceptable for duplicates of samples, the test material would be considered acceptable to use. This may be a calculated acceptance criteria based on 3 times the standard deviation of the mean or a set value like 20% RPD. No matter how you determine your duplicate acceptance criteria make sure you use colony counts not final calculated values in doing this. Other factors to consider when determining if a new material is suitable include: Are the colonies obtained typical, that is normal looking blue colonies? Are the colonies evenly distributed across the membrane surface? Are there an unusual number of non typical colonies present? Is there a pattern to the colony recoveries? For example are all the plates for the test materials significantly lower in counts than the reference lot? It is recommended that new consumables be tested as soon as possible after receipt to avoid problems if the materials are not acceptable. Once you determine that the new material is acceptable to use; you may begin to do so. Document the date the new lot # is put into use. Revised 2/06 North Carolina Wastewater/Groundwater Laboratory Certification Matrix Spiking Policy and Technical Assistance (4/6/2010) Policy Statement Unless the referenced method states a greater frequency, spike 5% of samples on a monthly basis. Laboratories analyzing less than 20 samples per month must analyze at least one matrix spike (MS) each month samples are analyzed. Prepare the MS from a reference source different from that used for calibration unless otherwise stated in the method. If MS results are out of control, the results must be qualified or the laboratory must take corrective action to rectify the effect, use another method, or employ the method of standard additions. When the method of choice specifies MS performance acceptance criteria for accuracy, and the laboratory chooses to develop statistically valid, laboratory-specific limits, the laboratory-generated limits cannot be less stringent than the criteria stated in the approved method. When spiking with multi-component standards, if the method does not specify the spiking components, the Laboratory Control Spike (LCS) and MS must contain all analytes that are reported. If the unspiked sample result is in the top 40% of the calibration range, the sample should be diluted and the MS prepared using the diluted sample. The recovery of the MS samples must be bracketed by the calibration range. The volume of spike solution used in MS preparation must in all cases be ≤ 10% 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 by calculation necessary. If the spike solution volume constitutes >1% of the total sample volume, the sample concentration or spike concentration must be adjusted by calculation. Technical Assistance Spike Preparation The spike concentration may be set at either 5 to 50 times the Method Detection Limit (as determined by the Method Detection Limit or MDL study) for the analyte, or at 1 to 10 times the ambient level (average concentration) of the analyte in samples. There are 3 options for preparing spikes: Option 1 (Recommended - easiest) - If the spike solution volume is equal to 1% or less of the total sample volume, direct subtraction of the unspiked sample is allowed. When the volume of the standard solution spiked into a sample or a sample extract is less than 1% of the total volume then the final concentration need not be adjusted (e.g., 10 µL of spike solution added to a 1 mL final extract results in only a negligible 1% change in the final extract volume). Option 2 - Adjust spike solution to a known volume with sample. In this case the sample concentration must be adjusted. When the volume of spike solution exceeds 1% of the total MS volume the sample concentration must be adjusted prior to determining spike recovery. Option 3 (Not recommended – most difficult) - Add spike solution to a full volume sample. In this case, the spike concentration must be adjusted. When the volume of spike solution exceeds 1% of the total MS volume the spike concentration must be adjusted prior to determining spike recovery. Spike Preparation Examples Option 1 - If the spike solution volume is equal to 1% or less of the total sample volume, direct subtraction of the unspiked sample is allowed. Option 1 Example: 0.5 mls of a 1000 mg/L standard spike added to 100 mls of sample has a theoretical value of 5 mg/L. (A) The spiked sample recovery is 5.1 mg/L (B) If the unspiked sample result is 0.5 mg/L (C) Theoretical value is 5.0 mg/L The Percent Recovery = spiked sample recovery (A) – unspiked sample result (B) divided by theoretical value (C) X 100 or 5.1 – 0.5 X 100 = 92% recovery A – B X 100 = Percent recovery 5.0 C Option 2 - Adjust spike solution to a known volume with sample. In this case the sample concentration must be adjusted. Option 2 Example 1: 10 mls of spike (concentration 50 mg/L) brought to 100 mls with sample the theoretical MS value is 5 mg/L. (A) The spiked sample recovery is 5.1 (B) If the unspiked sample result is 0.5 mg/L (C) % sample is 0.90 (sample volume used (90) divided by final volume (100)) (D) Theoretical value is 5.0 mg/L The Percent Recovery = spiked sample recovery (A) – (unspiked sample result (B) x % sample (C)) divided by theoretical value (D) X 100 or 5.1 – (0.5 x 0.9) X 100 = 93% recovery A – (B x C) X 100 = Percent recovery 5.0 D Option 2 Example 2: Larger spike volume 25 mls of spike (concentration 50 mg/L) brought to 250 mls with sample the theoretical MS value is 5 mg/L. (A) The spiked sample recovery is 5.6 (B) If the unspiked sample result is 0.5 mg/L (C) % sample is 0.90 (sample volume used (225) divided by final volume (250)) (D) Theoretical value is 5.0 mg/L The Percent Recovery = spiked sample recovery (A) – (unspiked sample result (B) x % sample (C)) divided by theoretical value (D) X 100 or 5.6 – (0.5 x 0.9) X 100 = 103% recovery A – (B x C) X 100 = Percent recovery 5.0 D Option 3 - Add spike solution to a full volume sample. In this case the spike concentration must be adjusted. Option 3 Example: 5 mls of a spike (concentration 100 mg/L) is added to 100 mls of a sample (105 mls final volume). (A) The spiked sample recovery is 5.1 (B) If unspiked sample result is 0.5 mg/L (C) Spike conc. adjustment is 0.9524 (sample volume (100) divided by sample + spike volume (105)) (D) Actual spike value is 4.7619 (Theoretical value (5 mg/L based on 100 ml sample) x C) The Percent Recovery = spiked sample recovery (A) x (sample volume divided by sample volume + spike volume (C)) – unspiked sample result (B) divided by Actual spike value (D) X 100 or (5.1 x 100 ) – 0.5 (A x C) – B X 100 = 91.5% 100+5 X 100 = 91.5% recovery D 4.7619 Corrective Action/Qualifications for MS Spike accuracy is usually based on a range of percent recovery (e.g., 80-120%). Refer to the method of choice for specific acceptance criteria for the matrix spikes until the laboratory develops or adopts statistically valid, laboratory- specific performance criteria for accuracy. If a MS fails, and the LCS is acceptable, qualify the data for the MS sample. Repeated failures for a specific matrix may require use of an alternate method or method of standard addition. Base the sample batch acceptance on the results of the LCS analyses (and other quality control results) rather than the MS alone, because the matrix of the spiked sample may interfere with the method performance. If a MS and the associated LCS fail, re-prepare and reanalyze affected samples. Post Digestion Spikes (PDS) Post Digestion Spikes (PDS) are used for some analyses (e.g., metals) to assess the ability of a method to successfully recover target analytes from an actual sample matrix after the digestion process has been performed. The PDS results are used with MS results to evaluate matrix interferences. The MS and PDS should be prepared from the same environmental sample. A PDS is not to be analyzed in place of a MS. Post Digestion Spikes must be reported as post-digested and must not be misrepresented as pre-digested spikes. (Exception: TCLP and SPLP samples are always spiked post digestion.) Corrective Action/Qualifications for Post Digestion Spikes In general, if the MS recovery for an analyte does not fall within the quality control acceptance range but the PDS recovery is acceptable, then a matrix affect (associated with the preparatory process) should be suspected and the unspiked sample results must be qualified on the basis of the matrix spike recovery. However, when historical data for the effect does not exist, the laboratory would normally be expected to perform a second digestion and reanalysis of the MS to confirm the result. The result would be confirmed if the MS recoveries and PDS recoveries for both sets of analyses were similar in magnitude and bias. When both the MS recovery and PDS recovery for a particular analyte falls outside of quality control acceptance range in the same manner (i.e., the PDS and MS failures are of similar magnitude and the direction of bias is the same), confirmatory analyses are unnecessary but the data must be qualified. Parameters Excluded from MS Requirements Acidity Alkalinity BOD/CBOD Aquatic Humic Substances Chlorophyll All Bacteriological Parameters Color – ADMI Color - PtCo Conductivity Dissolved Oxygen Ignitability All Residues Paint Filter Test Turbidity pH Temperature Salinity Sulfite Total Residual Chlorine Vector Attraction Reduction (All Options) (Field Laboratories and Field Setting analyses are exempt.)