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Procedures for Detection and Quantitation
Federal Advisory Committee on Detection and Quantitation Approaches and Uses in Clean Water Act (CWA) Programs Summary of Technical Work Group Conference Call #3 The next Technical Work Group call is scheduled for Wednesday, August 10, from 1:00 – 3:00 PMEDT. Number 877.915.3914 789659# Action Items Dick Reding will:
The subgroup on definitions of detection and quantitation was formed at the July 13 Technical Work Group meeting to work on definitions of detection and quantitation (Steve Bonde, Cliff Kirchmer, Ken Osborn, John Phillips, David Rocke, and Brad Venner, and Tom Georgian (DOD), invitee). In preparation for the August 10 conference call, the subgroup will:
Welcome and Introductions Robert Wheeler, facilitator, welcomed participants to the call . To allow Technical Work Group members who were attending the National Environmental Monitoring Conference i(NEMC) n Washington, DC to join the conference call, the meeting got underway a few minutes after 5:00 PM EDT. Mr. Wheeler conducted a roll call, and reviewed the agreed-upon protocols for the teleconference established on the June 24 call. (The protocols are listed in the June 24 meeting summary.) He reminded Technical Work Group members of their assignment from the federal advisory committee. He said Technical Work Group members were tasked with developing:
Report on National Environmental Monitoring Conference (NEMC) Dick Reding reported briefly on some talks given at the NEMC session on detection and quantitation: Richard Burrows gave an overview of the American Council of Independent Laboratories (ACIL) detection procedure, Steve Winslow described EPA’s Office of Water’s Lowest Concentration Minimum Reporting Level (LCMRL) procedure, and Dick described the federal advisory committee, and its process and status. Report of the Subgroup on Definitions and Discussion After noting that the subgroup on definitions had sent a draft subgroup product to the workgroup in advance of the call, entitled, “Detection Definitions,” dated 7/20/05, Mr. Wheeler asked John Phillips to describe how the product had been developed. Mr. Phillips explained that the subgroup had gone through each definition and had added a reference to identify the source of the definition. In some cases, the subgroup had added additional details, descriptions, or excerpts from the source document. The subgroup members had also discussed which definitions they might recommend to the Technical Work Group for the federal advisory committee meeting. He said that subgroup members had agreed the IUPAC definitions for detection were the most robust because they addressed both Type I and Type II errors. Mr. Phillips then referred to a second document that had been distributed in advance of the call, “Detection Limit Recommendations,” and clarified that it was his summary of the subgroup discussions – the subgroup had not reviewed or approved it. The discussions that followed focused on whether or not the definitions incorporated the concept of a method blank and bias or addressed false positives and false negatives. Whether to include or exclude formulae was also discussed. If the definitions include formulae, some members argued, it would be important to define the assumptions associated with those formulae. Otherwise, there was a risk that procedures could be developed without taking into considering the underlying assumptions. After discussion, Technical Work Group members agreed that federal advisory committee discussions would benefit from having a single document that presented the original definitions for each detection method with the source cited. The subgroup also agreed to create a second document that would include additional information, including the assumptions underlying the definitions and formulae. With respect to the definition for “uncertainty,” the Group agreed to include it in the glossary of terms. Looking ahead to quantitation, the subgroup agreed to format definitions of quantitation as they had the definitions of detection. John Phillips and Ken Osborn said they would take the lead in revising the documents in preparation for further subgroup discussion. Discussion of the Draft Characteristics-Procedure Matrix Mr. Wheeler then turned to the draft matrix of characteristics and procedures (dated Version 1, 6/29/05). He noted that John Phillips had sent comments about the characteristics to Dick Reding who had sent them out to the TWG. Mr. Wheeler called on Mr. Phillips to review his comments, primarily focused on adding clarity to several of the characteristics and providing terms that will be used for evaluating characteristics. The TWG agreed with Mr. Phillip’s suggestions and added the following comments:
The Technical Work Group members then discussed adding the following characteristics:
Cliff Kirchmer suggested considering the utility of adding complexity to the matrix versus keeping it simple for discussion at the federal advisory committee. Technical Work Group members agreed that it was important to have a common understanding of what each of the characteristics means before filling out the matrix. Mr. Reding suggested that workgroup members not on the definitions subgroup form another subgroup to develop descriptions of each of the characteristics. Members agreed and said they would draft materials for discussion at the next Technical Work Group meeting. Mr. Reding said he would take the lead on this new subgroup. Public Comment Mr. Wheeler invited observers to offer comments. Tom Georgian of the US Army Corps of Engineers suggested a simple definition for the Critical Value. Mr. Reding asked Mr. Georgian to send it to him via email. Wrap-up and Closing Mr. Reding said he had the call-in information for future conference calls and would send it to Technical Work Group members now as well as before each call. 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, thanked Technical Work Group members for their participation, and closed the meeting at 7:00 p.m. (EDT).
Attendance
Technical Work Group Members
Triangle Associates - Derek Van Marter and Robert Wheeler Observers
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