Analytical Methods

Whole Effluent Toxicity Methods Variability Studies and Variability Guidance

On October 16, 1995, EPA approved 17 test methods for measuring whole effluent toxicity (WET) under the Clean Water Act (60 FR 53529). This approval allowed laboratories to use these methods for general data gathering and compliance monitoring under National Pollutant Discharge Elimination System (NPDES) permits. However, two organizations challenged the approval of these methods in court and requested judicial review. On July 24, 1998, EPA and the two organizations reached a settlement agreement to resolve the judicial challenge. As part of this settlement agreement, EPA will conduct interlaboratory variability studies for 12 of the 17 approved WET methods, prepare guidance on analytical variability, and prepare guidance on specific WET technical issues.

On August 24, 1998, a public docket for Whole Effluent Toxicity Methods Variability Studies and Variability Guidance was created that included the following background and support documentation: the settlement agreement, the WET test method manuals, a draft study plan for the WET interlaboratory variability study, and a charge to the peer review panel. Peer review and public comment on the draft study plan was received through November 30, 1998. EPA considered these comments and created a final version of the study plan. On June 11, 1999, the final study plan was placed in the public docket. The Final Study Plan for Determining Interlaboratory Variability of the EPA Short-Term Chronic and Acute Whole Effluent Toxicity Test Methods along with guidance documents and other support documents may be downloaded below or viewed in the public docket.

Interlaboratory Variability Studies

Post Promulgation Docket Index for Whole Effluent Toxicity Methods Variability Studies and Variability Guidance (PDF, 8K)
This index provides the complete list of documents available for public review at the US Environmental Protection Agency Water Docket, 401 M Street, SW, Washington, DC   20460.

Final Study Plan for Determining Interlaboratory Variability of the EPA Short-Term Chronic and Acute Whole Effluent Toxicity Test Methods (PDF, 105K)
On June 11, 1999, the Final Study Plan was placed in the public docket.  The study plan was finalized by EPA in response to peer review and public comment received on the draft study plan (October 9, 1998 version).  The study plan outlines the study objectives, study management, procedures for selecting laboratories, preliminary testing, sample preparation and distribution, conduct of each test method, and data reporting and evaluation procedures.

Settlement Agreement between Edison Electric Institue and Western Coalition of Arid States and the US Environmental Protection Agency, July 24, 1998 (PDF, 38K)
On July 24, 1998, EPA, the Edison Electric Institue, and the Wesetern Coalition of Arid States reached an agreement to settle a challenge to EPA's approval of 17 WET test methods.  The agreement requires EPA to conduct additional interlaboratory variability studies for 12 of the 17 approved WET methods, prepare guidance on analytical variability, seek peer review for technical decisions, and publish a series of Federal Register notices that address the WET final rule.

Charge to Reviewers: Interlaboratory Study of Whole Effluent Toxicity Test Methods, October 9, 1998 (PDF, 18K)
As required by the settlement agreement EPA is seeking peer review of the document titled, Appendix A: Study Plan for Determining Interlaboratory Variability of the EPA Short-Term Chronic and Acute Whole Effuent Toxicity Test Methods, October 9, 1998 (PDF, 150K).  The study plan outlines the procedures for selecting laboratories, sample preparation and handling, and conducting each test method.   Peer review will ensure that the study plan employs credible and appropriate science to evaluate each WET test method.  The formal charge to the Peer Review Panel is to objectively review whether the study design (Appendix A) effectively assesses method precision, test completion rate, and the rate at which the tests indicate "toxicity" when measuring non-toxic samples.

Guidance Documents

Understanding and Accounting for Method Variability in Whole Effluent Toxicity Applications Under the National Pollutant Discharge Elimination System
This document provides guidance to NPDES regulatory authorities and persons interested in whole effluent toxicity testing.

Whole Effluent Toxicity Test Methods Guidance: Notice of Availability (July 28, 2000)

Science Policy Council Handbook:   Peer Review, EPA 100-B-98-001, January 1998 (PDF, 343K)
On June 7, 1994, the EPA issued a Peer Review Policy Statement.  The overall objective of the Peer Review Policy is to enhance the quality and credibility of Agency decisions by ensuring that scientific and technical work products that support EPA decisions receive peer review by independent scientific and technical experts.  To help EPA state and managers implement this policy, EPA's Science Policy Council (SPC) prepared this Peer Review Handbook to provide guidance on organizing and conducting peer reviews.

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