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Procedures for Detection and Quantitation

Technical Workgroup

Federal Advisory Committee on Detection and Quantitation Approaches and Uses in Clean Water Act (CWA) Programs

Summary of Technical Work Group Conference Call #12
November 9, 2005
1:00 – 3:00 p.m. EDT

The next Technical Work Group call is scheduled for Wednesday, November 9, from 1:00 - 3:00 PM EDT.

Action Items

Richard Reding will

Jim Pletl will further refine the description of characteristics based on comments from Technical Work Group members and redistribute a draft for discussion next week.

Ken Osborn will send to Triangle a definition for "Reliable Detection Limit" for the glossary of terms.

The Single Lab Subgroup (Richard Burrows - lead, Cliff Kirchmer, Ken Osborn, Brad Venner, David Kimbrough and John Philips) will review the revised purposes and objectives (see below), adding clarifications to #4, if appropriate. The subgroup will also revise its product in preparation for distribution to the federal advisory committee, placing particular emphasis on the policy questions needing discussion at the December 8-9 committee meeting.

The Multi Lab Subgroup (Larry LaFleur - lead, Bob Avery, Jim Pletl, Richard Rediske and Steve Wendelken) will revise its product in preparation for distribution to the federal advisory committee, placing particular emphasis on the policy questions needing discussion at the December 8-9 committee meeting.

Triangle will:

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Welcome and Introductions

Robert Wheeler, facilitator, welcomed participants to the call at 1:00 PM EST. He conducted a roll call of Technical Work Group members and observers, and briefly reviewed the agenda for the meeting. Mr. Wheeler emphasized the purpose of the meeting was to hear an update from EPA regarding internal discussions, updates from the two subgroups on the status of products for the December federal advisory committee meeting, and to discuss modifications to descriptions of characteristics.

Mr. Wheeler confirmed with Richard Rediske that he did want to participate in the Multi-lab subgroup, and Mr. Rediske confirmed that was true.

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Draft Meeting Summary

Mr. Wheeler asked for comments to the draft October 19, 2005 Technical Work Group meeting summary. Cliff Kirchmer, representing states, suggested revisions to the second paragraph on page 4. The group agreed that a bullet should be added to the group's discussion of revisions to the descriptions of characteristics indicating that the "Defensibility" category would remain, but would not be evaluated at this time. The group approved the October 19, 2005 summary, with revisions.

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EPA Management Update

Richard Reding of EPA reported on feedback from management at EPA regarding the pilot study. He said one of the concerns is that there are currently too many procedures that the group is considering for pilot testing. Although he explained that the number of laboratories participating and the number of samples tested is what really drives the cost, the perception is that since the procedures are so similar there should be an attempt to narrow the procedures to a number that truly tests those that are different.

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Purposes and Objectives of a Pilot Study

Members of the Technical Work Group discussed the purposes and objectives of the pilot study, using the list revised by the Multi-lab Subgroup. After considerable discussion, the group agreed to the following list of questions for purposes and objectives of the pilot study.

  1. Is the procedure clearly written?
  2. Can the data be easily processed in the laboratory?
  3. Was the procedure performed correctly?
    • [Note: the Technical Work Group discussed at length the intent of this question. Members agreed that it was appropriate to have pre- and post-study questions. This question falls into the latter category. It is an attempt to evaluate the performance of the procedure as it was written. If there is great variation in the analysis of the performance of the procedure, the Technical Work Group agreed that could be due to variation in interpretation of the written procedure and/or that the procedure was poorly written.]
  4. Does the experimental design unduly influence the outcome of the study?
    • Additional clarifying questions from the Multi-lab Subgroup include:
      1. Type of method (censored, uncensored, etc.)
      2. Works equally well if analyte recoveries are uniformly low, uniformly high, or highly variable
      3. Choice of outlier test (not mandated by procedure?)
      4. Number of different concentrations tested
      5. Number of replicates per concentration tested
      6. Magnitude of concentrations tested
      7. Relative relationship between spikes (0.25x, .5x, x, 2x, 4x, etc.)
      8. Number of laboratories
      9. Number of analysts per study or per laboratory
      10. Number of instruments per study or per laboratory
      11. Sample preparation
      12. Number of different days for which analyses are conducted per laboratory
      13. Time span over which analyses are conducted per laboratory (week, month, quarter, year)
      14. Number of data points per detection or quantitation limit calculation
    • Additional clarifying questions from the Single-lab Subgroup include:
      • To be added, if appropriate.
  5. Does the procedure achieve its intended purpose?
  6. Does the procedure work for all different types of analytical methods?
  7. Does the procedure work if applied to real world sample matrices? (This may also include a broader question evaluating how the procedure applies to real world matrices.)

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Report from Multi-lab Subgroup

Larry LaFleur reported for the Multi-Lab Subgroup reviewing the subgroup progress report sent via email to Technical Work Group members. He identified specific questions the subgroup had for the Technical Work Group; he particularly focused on whether the general concepts for a study design made sense, and whether the step-wise approach appeared feasible.

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Report from Single-lab Subgroup

Richard Burrows reported for the Single-Lab Subgroup saying that members had received minutes from the two conference calls the subgroup had. The subgroup started by thinking through the types of analytical methods the subgroup would like evaluated. The subgroup expressed concern with the amount of work involved in a pilot test, but did not go into great detail.

Mr. Burrows posed a priority policy question for the Technical Work Group's, and likely the federal advisory committee's consideration: Should the detection and quantitation procedure identify the absolute lowest possible level that a single lab can detect or quantitate; or should a procedure verify that the lab can actually detect or quantify at their stated detection or quantitation level? Or both?

The second question might also be phrased in the context of a procedure that demonstrates that the lab can achieve a specific (e.g. prescribed MQO) detection or quantitation. Mr. Burrows said these are two very different questions and have significant implications for future discussions.

Mr. Wheeler summarized the discussion and reminded the subgroups that they would need to complete a product for discussion and approval at the November 16 Technical Work Group meeting. The products would then be sent to federal advisory committee members in advance of the December meeting.

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Discussion of Revisions to Descriptions of Characteristics

Mr. Wheeler asked Jim Pletl to briefly review the revisions he had made based on the last Technical Work Group conference call, including other comments received since that time. Mr. Pletl identified several revisions he had made based on comments, and asked the group to review a new question posed on page 2 under "Uncertainty Calculated." He asked members to review the revised document and send to him via email any final comments for discussion at the November 16 conference call.

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Public Comment

There were no public comments.

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Wrap-up and Closing

Mr. Wheeler reminded participants that the dates and times (all are EDT) of future Technical Work Group meetings are as follows:

Mr. Wheeler briefly noted the action items from the call, and said the agenda for the next call would focus on revisions to the descriptions of the characteristics, finalizing products from the subgroups, and revisions to the glossary of terms. He thanked Technical Work Group members for their time and closed the meeting at 3:00 p.m. EST.

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Attendance

Technical Work Group Members

Triangle Associates: Derek Van Marter and Robert Wheeler

Observers

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