March 1 9 , 201 4

Adrian Hanley USEPA Office of Water 1301 Constitution Ave NW Washington, DC 20004

Dear Adrian :

The NELAC Institute is providing the attached proposed revision to the Method Detection Limit (MDL) procedure published in 40 CFR Part 1 36 Appendix B. TNI is requesting the Agency replace the current procedure with this one. Our stakeholder community of laboratories, state agencies, regulated industry and scientists believe this revision represents a significant improvement over the curre nt MDL procedure

. This new procedure is vitally important to the laboratory community in general and to the regulated NPDES dischargers they serve. We would specifically request this change be made in the next Method Update Rule.

The concept of an MDL, fir st developed by the Agency in 1979, is critical to ensuring the regulated industry provide reliable monitoring data. Laboratories need a reliable procedure that they believe will provide confidence in both their qualitative identifications as well as state ment s that reflect a non

- detect and we believe this procedure achieves that goal. Replacing the current procedure with this revised procedure will benefit TNI’s 800 plus members as well as the public as a whole.

By way of background on the process, i n 2011

, TNI entered into a cooperative agreement with the Agency to develop measurement tools and accreditation standards. As part of this effort, TNI formed a new expert committee to “ develop consensus standards that will establish requirements for fundamental measurement practices such as Limit of Detection (LOD), Limit of Quantitation (LOQ), and instrument calibration to reduce quality system vulnerabilities. ” To date, that effort has resulted in proposed revisions to the instrument calibration requirements i n TNI’s accreditation standards applicable to laboratories tha t perform chemical measurements. The next stage now in progress will be a working draft standard for LOD and LOQ.

TNI is accredited by the American National Standards Institute as a consensus st andards organization, and TNI’s Chemistry Committee conforms to all requirements of OMB Circular A

- 119. A membership roster of the committee showing stakeholder representation is attached to this letter.

The committee believes the Method Detection Limit pr ocedure in 40 CFR Part 136 is, and will continue to be, the most frequently used procedure for determining an LOD . As you know, several of the members
of TNI’s committee also served on the Federal Advisory Committee on Detection and Quantitation (FACDQ)

. Based on recommendations in the FACDQ final report, TNI’s Chemistry Committee initiated an effort to revise the language in Appendix B of Part 136 to establish a new procedure that addressed the shortcomings of the current MDL procedure

.

PO Box 2439, Weatherford, TX 76086  817

- 598

- 1624
www.nelac

- insti tute.orgOn August 2 2 , 201 3, TNI posted a draft version of a revised procedure on the TNI website with the opportunity for the public to provide comments. A copy of the proposed procedure was also provided to EPA’s Environmental Laboratory Advisory Board. The proposed procedure has been presented at national meetings such as the Envi ronmental Measurement Symposium as well as many regional meetings such as th e annual meeting of the Florida Society of Environmental Analysts. There has been overwhelming support for TNI’s efforts from the public

. TNI’s Chemistry Committee developed the proposed procedure using our consensus process. The committee believes this document represents the consensus opinion of all the stakeholders who participated in the effort. TNI is providing this documen t with no copyright restrictions as we believe this procedure is fundamental to the environmental monitoring community.

Please feel free to contact me if you have any questions

.
Sincerely,

Jerry Parr
TNI Executive Director

CC: Jan Matuszko, EASB, Bra nch Chief Janet Goodwin, TSB, Branch Chief. Lemuel Walker, EAD Richard Burrows, TestAmerica, Inc. Sharon Mertens, Milwaukee Metropolitan Sewerage District

PO Box 2439, Weatherford, TX 76086  817

- 598

- 1624
www.nelac

- insti tute.org

## Chemistry Expert Committee

The mission of this committee is to improve the technical quality of envi ronmental testing methodologies by providing tools (e.g., detection, quantitation and calibration) that assure the quality of data, which may be adopted by federal and state regulatory agencies.

Name Organization Stakeholder Group Sub

- Group

Richard Burro ws TestAmerica, Inc. Laboratory Commercial Laboratory

Francoise Chauvin New York City DEP Laboratory Municipal Laboratory

Dan Dickinson New York State DOH Accreditation Body NELAP Accreditation Body

Tim Fitzpatrick Florida DEP Laboratory State Laborato ry

Nancy Grams Ad vanced Earth Technologies, Inc. Other Consultant

John Phillips Ford Motor Co Other Regulated Industry

Gary Ward Oregon SPHL Accreditation Body NELAP Accreditation Body

Brooke Connor US Geological Survey Other Federal Agency

Mandi Edwa rds Envirochem Laboratories Laboratory Commercial Laboratory

Anand Mudambi US EPA Other Federal Agency

Scott Siders Illinois EPA Accreditation Body NELAP Accreditation Body

PO Box 2439, Weatherford, TX 76086  817

- 598

- 1624
www.nelac

- insti tute.org