Approval of Conditional Data from the National Water Quality Laboratory Lab Code 9090 -- Low-Level Volatile Organic Chemicals In Reply Refer to: Mail Stop 412 May 1, 2000 Office of Water Quality Technical Memorandum 2000.06 Subject: Approval of Conditional Data from the National Water Quality Laboratory Lab Code 9090 -- Low-Level Volatile Organic Chemicals BACKGROUND It is the policy of the Office of Water Quality (OWQ) that water quality analytical data approved by the U.S. Geological Survey (USGS) is produced by laboratories approved according to OWQ Technical Memoranda (TM) 98.03 & 2000.02, who are using analytical methods approved according to OWQ TM 98.05. In brief, the methods approval process accepts all methods of the US Environmental Protection Agency, ASTM, Standard Methods, and methods approved by the USGS. OWQ TM 98.05 also provides for USGS approval of new water quality analytical methods. PURPOSE OF MEMORANDUM This memorandum announces an exception to the methods and data approval policy of the OWQ. This exception is for the volatile organic chemicals (VOC) method specified by the National Water Quality Laboratory (NWQL) Lab Code 9090, which, upon USGS approval on October 1, 1996, became Schedule 2020 (Connor, et.al., 1998). The exception is that data produced under Lab Code 9090 prior to October 1, 1996 are now considered to be approved, and can now be reported to the public in data bases and be included in data reports. This exception is based on several factors: 1. All data reported using Lab Code 9090 are similar to data produced using Schedule 2020, and all but 8 compounds have data quality identical to that found in the approved Schedule 2020. These 8 compounds had differing censoring levels applied due to laboratory background concentrations as described in detail in OWQ TM 98.04. These 8 compounds are: benzene, ethyl benzene, toluene, xylenes, 1,4-dichlorobenzene, methylene chloride, acetone, and carbon disulfide. 2. A series of open discussions and data reviews between the National Water Quality Assessment Program (NAWQA), the OWQ, and the NWQL revealed no additional data quality issues with any of the Lab Code 9090 data. 3. The analytical method did not change throughout the entire period, both before and after October 1, 1996. GUIDANCE AND INTERPRETATION Data produced under NWQL Lab Code 9090 are identified with a Method Code of 'Z'. This Method Code shall not be changed so that these data can always be associated with Lab Code 9090. These data have also had their National Water Information System (NWIS) District processing Status (DSTAT) set to 'Z' so that these data would not be made available to the public. This DSTAT flag can now be reset to 'R' and the data made available as USGS-approved data. Although these data are correct as reported, the different censoring criteria applied to 8 compounds could result in misinterpretations unless the guidance provided in OWQ TM 98.04 is followed. Please consult that memo for more details. In summary, all data produced using Lab Code 9090 are no longer considered conditional. They are now approved and can be released and used along with other approved data. REFERENCES Connor, Brooke, Rose, Donna L., Noriega, Mary C. Murtagh, Lucinda K., Abney, Sonja R. 1998. Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory?Determination of 86 Volatile Organic Compounds in water by Gas Chromatography/ Mass Spectrometry, Including Detections Less Than Reporting Limits. U.S. Geological Survey, Open File Report #97-829, 78 p. OWQ TM 98.03 - Policy for the Evaluation and Approval of Production Analytical Laboratories OWQ TM 98.04 - Guidance for Interpretation of NWQL Schedule 2020 and 2021 VOC Data OWQ TM 98.05 - Policy for the Approval of U.S. Geological Survey (USGS) Water-Quality Analytical Methods OWQ TM 2000.02 - Policy for the Reimbursement of Costs for Quality Assurance of Water-Quality Analytical Laboratories Janice R. Ward /s/ Acting Chief, Office of Water Quality This memorandum does not supercede any other OWQ Technical Memorandum. Distribution: A, B, DC, District and Regional Water Quality Specialists, NAWQA NLT, NAWQA Synthesis Teams, NAWQA Project Leaders, and OWQ Staff