Citation:

Stelma Jr., G N. THE EPA MICROBIAL SOURCE TRACKING DOCUMENT. Presented at EPA's National Beaches Conference, San Diego, CA, October 14, 2004.

Impact/Purpose:

Develop a rapid (same day), sensitive and accurate method for detecting and measuring fecal contamination of recreational water.

Description:

Beach closures or violations of total maximum daily loads of fecal organisms in watersheds frequently generate a need to identify the major sources of contamination or, at least, determine whether the source is human or animal. A few years ago E. coli ribotyping was the only method available for microbial source tracking (MST). Recently, however, a number of diverse methods are reported to be effective for MST; and it has become difficult for beach managers and other local officials to choose the method that is best for their specific needs. The USEPA is writing a guidance document to assist the users of MST methods in choosing the most appropriate method for their individual beaches or watersheds. The MST guide document contains descriptions of each published method, including references; the assumptions on which the methods are based; the limitations of each method; data collection and analyses and method performance. The final chapter provides decision criteria and includes a "decision tree" which guides the reader through the various scenarios in which MST may be useful. Each decision point in the tree contains a menu of the most appropriate methods for the user's needs. The document is comprehensive, including both library-dependent and library-independent molecular methods, as well as library-dependent phenotypic methods.

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