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


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.


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,, 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.


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.


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