of drinking water are irregular and are not supported by adequate research; and (3) proposed monitoring requirements for groundwater are not adequately protective for viral pathogens.

Based on these conclusions, the committee provides the following recommendations regarding the development of a phased approach to monitoring microbial water quality:

  • EPA should invest in a long-term research and development program to build a flexible tool box of indicators and methods that will serve as a resource for all three phases of investigation identified in this report.

  • This tool box should include the following: (1) the development of new indicators, particularly direct measures of pathogens that will enhance health risk confirmation and source identification; (2) the use of coliphages, as suggested by EPA’s Science Advisory Board, in conjunction with bacterial indicators as indicators of groundwater vulnerability to fecal contamination; and (3) the use of routine microbiological monitoring of surface water supplies of drinking water before as well as after treatment.

  • A significant portion of that investment should be directed toward concentration methods because existing technology is inadequate to measure pathogens of concern at low concentrations.

  • Consistent with previous related recommendations, EPA should invest in comprehensive epidemiologic studies to (1) assess the effectiveness and validity of newly developed indicators or indicator approaches for determining poor microbial water quality and (2) assess the effectiveness of the indicators or indicator approaches at preventing and reducing human disease.

  • EPA should develop a more proactive and systematic process for addressing microorganisms on the Drinking Water Contaminant Candidate List (CCL). The EPA should (1) prepare a review of published methods for each CCL microorganism and groups of related microorganisms, (2) publish those reviews on the Internet so researchers and practitioners can use them and comment on how to improve them, and (3) promote their use in special studies and monitoring efforts.

These conclusions and recommendations should not be taken as an excuse to either cling to or abandon current indicator systems until research develops new approaches. On the contrary, the committee recommends a phased approach to monitoring, as both a means to make existing indicator systems more effective, and to encourage the successive adoption of new, more promising indicator systems as they become available.



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