PROGRAMS AND PLANS--Review of enzyme-based field screening methods

In Reply Refer To:                         November 10, 1988
WGS-Mail Stop 412



OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM NO. 89.02

Subject:  PROGRAMS AND PLANS--Review of enzyme-based field 
                              screening methods

The purpose of this memorandum is to transmit the attached 
review of enzyme-based field screening methods prepared by 
Paul Capel.  At this time, the Office of Water Quality does 
not have enough information about the methods to make 
recommendations about their use in Water Resources Division 
projects.  However, because of the potential usefulness of 
these methods, the Office of Water Quality has prepared this 
information and is sponsoring a study to validate the 
techniques.  The methods are still experimental and have not 
been standardized; therefore, data from the enzyme-based 
methods cannot be entered into WATSTORE.  If and when the 
methods are adequately validated and precision, accuracy, and 
interferences for each method have been determined, the 
Office of Water Quality will prepare a technical memorandum 
that provides specifics for both using the methodology and 
storing resultant data in WATSTORE.

The enzyme-based methods may be useful as research tools or 
for field screening.  However, field tests with enzyme kits 
are not meant to be quantitative and do not replace 
laboratory analyses.  Data from the enzyme kits used in 
interpretive reports must be properly explained and 
qualified.  For example, the report should indicate that the 
kits respond to the presence of a group of compounds, and 
these compounds and their approximate detection limits should 
be listed in the report.  The report should also note that a 
positive response provides no information about which 
compound or compounds may have elicited the response.  In 
other words, the test does not give any information about the 
concentration of a specific substance in the sample.  If a 
sample is tested and no response is obtained, all compounds 
which the kit can detect are at concentrations below the 
minimum detection limit for the test.  Data from such a test 
should be reported as less than the detection limit for all 
compounds in the test suite.

If there are any questions or comments about use of the 
enzyme-based kits, please contact Paul Capel at 612-229-2646 
or EDOC address CAPEL.




                                David A. Rickert

Attachment

Distribution:  A, B, S, PO, FO

Key Words:  field tests