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Addendum 3 <br />Quality Control Requirements for Laboratories Performing Microbiological Testing <br />In addition to the quality control requirements outlined in Chapter 5 of the NELAC Standards, <br />the following quality control measures shall be implemented for this Contract. Note: "Sample" <br />refers to samples that have been either collected or analyzed under the terms of this Contract. <br />1. All microbiological analyses must conform to the requirements for facilities, personnel <br />qualifications, equipment specifications and quality control measures discussed in AWWA <br />Standard Methods 20`h edition, section 9020. <br />2. Quality Control Blanks <br />a. If the membrane filter technique is used, the sample set(s) shall be associated with a <br />beginning and ending filtration blank. <br />b. The results of any blank must be < 1 CFU/100 mL or the associated sample results must <br />be reported with the appropriate qualifier from Chapter 62-160, F A.C. <br />3. Laboratory Quality Control Duplicates <br />a. At least 10% of the samples (or one per test run) shall be duplicated. <br />b. All duplicate results shall be evaluated per method specifications using the precison <br />criterion. The range of the transformed duplicates shall not exceed the precision <br />criterion established by the laboratory. In the event that laboratory duplicate agreement <br />is not observed, the laboratory must investigate the poor precision and report the results <br />with appropriate qualifiers and/or comments. <br />c. Field Quality Control Duplicates or Replicates - In the event that agreement (less than or <br />equal the laboratory established precision criterion) is not observed between results from <br />field -generated replicate samples, the laboratory must investigate the replicate analyses <br />to determine that poor precision is not due to a laboratory error and report the results <br />with appropriate qualifiers and/or comments. The laboratory shall use the analytical <br />method specifications for precision control as a guide to evaluation of the field generated <br />replicate results. <br />4. Colony Counts <br />a. In addition to the requirements listed below, all analytical results shall be calculated by <br />the procedures established in the microbiological method(s) approved for the Contract <br />and listed in the planning document. <br />b. The laboratory shall make every attempt to ensure that colony counts are in the ideal <br />range of 20 — 60 colonies per plate. Reported values from colony plate counts outside <br />this range shall be qualified with a "B' (unless the reported value is from a 100 mL <br />sample and the count is Tess than 20) <br />c. If all counts are above 60, the result shall be calculated and reported from the highest <br />dilution. This result must be reported as "estimated' . <br />d. The laboratory shall follow the reporting requirements specified in the method for other <br />results that are outside the ideal range (item 5 b. above) <br />e. If the sample result is "too numerous to count (TNTC)" the laboratory shall report the <br />filtration volume with the data qualifier "Z" <br />f. Colony counts from samples that have been verified shall be adjusted based on the <br />verification results as specified in the analytical method approved for this Contract and <br />listed in the planning document. <br />DEP Agreement No. LP###, Attachment H, Page 12 of 12 <br />