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Water: Alternate Test Procedures

Alternate Test Procedures: Questions and Answers


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How do I write a method in EPA format?

The Guidelines and Format for Methods to be Proposed at 40 CFR part 136 or part 141 (PDF) (60 pp, 386K) (the "Method Guidelines and Format"; July 1996) have been prepared to promote consistency among analytical methods and to streamline the method promulgation process.


How do I ask EPA to review my method under the CWA ATP Program?

Under the CWA part of the Alternate Testing Program (ATP), EPA has provided detailed guidance about the kind of information the Agency needs to evaluate methods for potential approval. Methods evaluated under the ATP program need to go through notice and comment rulemaking before they are incorporated into CWA regulations. You may find this information in three protocols: two for chemical methods, and one for microbiological methods:

  1. Protocol for EPA Approval of New Methods for Organic and Inorganic Analytes in Wastewater and Drinking Water (PDF) (61 pp, 236K) March 1999
  2. Protocol for EPA Approval of Alternate Test Procedures for Organic and Inorganic Analytes in Wastewater and Drinking Water (PDF) (61 pp, 222K) March 1999
  3. EPA Microbiological Alternate Test Procedure Protocol for Drinking Water, Ambient Water, and Wastewater Monitoring Methods (PDF) (94 pp, 835K) September 2010

Note: The EPA does not have a protocol for toxicity testing under EPA's Whole Effluent Toxicity (WET) program.

Before submitting a method to EPA for an ATP review, a developer confers with EPA to design a method validation study. This study tests the new or modified method in several representative matrices and independent laboratories.

The method also must also be written in a standard format that includes all of the steps in an approved method, such as sample and data handling, and quality assurance requirements (Guidelines and Format for Methods to be Proposed at 40 CFR Part 136 or Part 141 (PDF) (60 pp, 386K) (July 1996).

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Is a method that is reviewed under the CWA ATP program an approved method?

No, the method must be approved through rulemaking before the method may be added to 40 CFR Part 136 as an approved CWA method.

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Are there any exceptions to rulemaking before use of an alternate test procedure?

Yes, but only for wastewater methods. Approval for nationwide use requires a rulemaking process. In the interim, a facility may apply to an EPA Region for a limited-use ATP approval letter, i.e. for use at that facility. Generally it is not necessary for the limited-use ATP applicant to submit data, or do a side-by-side comparison, if the method has already been reviewed under the CWA ATP program which requires multi-lab and comparability data.

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Why does EPA have two validation protocols for chemical methods?

One protocol covers modifications to approved methods that require EPA review and subsequent approval through rulemaking. Validation procedures for these modified methods are described in the "ATP Method" validation protocol (PDF) (61 pp, 222K).

The other protocol covers methods that use a new determinative technique, which usually means that the method uses a detector different from any detector used in existing approved methods. Validation procedures for these new methods are described in the "New Method" validation protocol (PDF) (61 pp, 333K).

New methods and ATP methods (i.e., a modification to an approved method) must be approved through rulemaking before nationwide-use.

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What is "136.6" Method Flexibility?

Many approved methods provide the flexibility to modify and use that method without prior approval of the modification. In 2007, EPA amended the wastewater regulations at 40 CFR 136.6 to describe additional (and to clarify existing) flexibility to modify any Part 136 chemical method without prior review.

See also Flexibility to Modify CWA Methods memo (PDF) (6 pp, 75K) (November 2007).

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Does 136.6 flexibility to modify methods only apply to CWA chemical methods?

Yes. This flexibility does not apply to drinking water methods, or to CWA microbiological or biological methods.

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Where can I find the Guide to Method Flexibility document?

You can find the Guide to Method Flexibility here.

How does EPA determine the equivalency of an ATP for a method defined parameter with a different determinative step than the EPA approved method?

EPA is developing a protocol for evaluating the equivalency of test procedures under the Clean Water Act program for method defined parameters with a different determinative step than the approved method in 40 CFR Part 136.  This protocol will especially focus on the amount and type of data (including QC) that will be needed to establish equivalency of the new method to the approved Part 136 method(s) and the statistical procedures that will be used to evaluate equivalency.  EPA anticipates this new method equivalency protocol for method defined parameters with a different determinative step will be drafted by the end of calendar year 2013.

EPA also encourages Voluntary Consensus Standards Bodies (VCSBs) to consider this forthcoming equivalency protocol when submitting methods to be considered for approval at Part 136.  EPA considers methods from VCSB’s and other Federal Agencies under the National Technology Transfer and Advancement Act (NTTAA) for inclusion in Part 136.  Once the protocol is established, EPA will use it to evaluate equivalency of all new methods for method defined parameters with a different determinative step considered for approval at Part 136.

EPA will continue to accept requests to evaluate new ATP applications for method defined parameters including those with a different determinative step than the existing method in Part 136 (as well as submissions from VCSBs) in the interim while the protocol is being completed.  However, parties should be aware that EPA may delay its final determinations on such new requests and may request additional data as the new protocol is developed and the data requirements are clarified.

Additional Information

For additional information, please contact Lemuel Walker (walker.lemuel@epa.gov) at 202-566-1077.

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