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Water: CWA Methods

Fact Sheet: Pumpkin Book

EPA-821-F-07-002; March 2007

EPA is making available a document to assist users of Clean Water Act (CWA) EPA chemical methods with technical advice on documenting and resolving matrix interferences.


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In 1993, EPA published a document titled "Guidance on Evaluation, Resolution, and Documentation of Analytical Problems Associated with Compliance Monitoring". The document was also known as the "Pumpkin Book" because of its pumpkin-colored cover.

The new EPA document, "Solutions to Analytical Chemistry Problems with Clean Water Act Methods" is a revision of the "Pumpkin Book". It represents significant improvements to the earlier document because it includes more information on inorganic chemistry; specific references to regulatory text that supports a performance-based approach to method modifications, and offers updated solutions to analytical problems.

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Purpose of the Technical Document

This technical document recommends ways to document the existence of a matrix or analytical problem with a CWA sample analysis, and mitigate these problems.

The advice in this document does not alter any otherwise applicable statutory or regulatory requirements, nor does it impose legally binding requirements on EPA, States, Tribes, or the regulated community.

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For More Information

You can find the "Solutions to Analytical Chemistry Problems with Clean Water Act Methods (PDF) (62 pp, 458K) here. The Appendices are also available (PDF) (9 pp, 274K).

Contact Lemuel Walker (walker.lemuel@epa.gov) at the U.S. EPA Office of Water, Engineering and Analysis Division (4303T), 1200 Pennsylvania Avenue NW, Washington, D.C. 20460.

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