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Water: Microbial

Microbial (Pathogen)

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The Safe Drinking Water Act (SDWA) and the Clean Water Acts (CWA) address microbial contamination of the nation's waters. The CWA enables protection of surface water for drinking water, recreational, and aquatic food source uses. The SDWA enables regulation of contamination of finished drinking water and protection of source waters.

Programs under the two Acts have historically followed separate paths using differing indicators of contamination and differing approaches. Concerns about future increases in microbial contamination and potential for emergence of new threats create a need to consider a strategy for the future that unites the influence of the two programs. Objectives of the strategy are to address all important sources of contamination, anticipate emerging problems, and use program and research activities efficiently to protect public health.

You can access a variety of sound scientific assessments that are used to protect the public from exposure to harmful levels of pathogens in ground and surface waters, food sources, and finished drinking water.

You may also access information on our Microbiology website.

Review of Coliphages as Possible Indicators of Fecal Contamination for Ambient Water Quality (PDF) (129 pp, 1MB)

This is a literature review of the scientific information that EPA will evaluate to develop coliphage-based ambient water quality criteria for the protection of swimmers.  It generally indicates that coliphages are equally good indicators of fecal contamination as EPA’s currently recommended criteria for E. coli and enterococci. In addition, coliphages are better indicators of viruses in treated wastewater than bacteria. While EPA conducts its evaluation of coliphages as possible viral indicators for water quality, we continue to recommend that states adopt our 2012 recreational water quality criteria into their water quality standards.  Stakeholders may send additional data for EPA to consider in the development of future coliphage-based ambient water quality criteria by June 15, 2015. Please email all information to Rec_Criteria@epa.gov or upload it directly to regulations.gov, docket number EPA-HQ-OW-2015-0300.  

Microbial Risk Assessment Tools, Methods, and Approaches for Water Media

EPA is providing this information to assist risk assessors and scientists in the development of rigorous and scientifically defensible risk assessments for waterborne pathogens. The document describes a human health risk assessment framework for microbial hazards in water media (e.g., pathogens in treated drinking water, source water for drinking water, recreational waters, shellfish waters, and biosolids) that is compatible with other existing risk assessment frameworks for human health and chemical hazards. Risk assessment is a science-based tool and is used to help managers explore the relative merits of various management alternatives, identify important gaps in knowledge, and inform regulatory actions. This document does not address microbial indicators of fecal contamination such as E. coli, enterococci, and bacteriophage.

Microbial Risk Assessment Thesaurus

Federal and international agencies, private sector organizations, and academics use terms and definitions in microbial risk assessment differently. This Thesaurus is a compendium of risk assessment terms found in frameworks, methodologies, and assessments. It provides insight into how various entities use specific microbial risk assessment terms in their activities and helps those responsible for such assessments both conduct and communicate about them more effectively.

Water Quality Standards and Implementation

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Drinking Water Regulatory Support Documents

Criteria documents and guidance for drinking water contaminants provide information so preliminary decisions can be made as to whether the contaminant is a significant health threat via drinking water exposure and whether sufficient data exists to perform quantitative risk assessments.

Criteria documents and guidance for surface waters provide information to help states adopt water quality standards that protect the health of people who recreate in water.

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Drinking Water Health Documents

Health Advisories serve as informal technical guidance to assist federal, state, and local officials responsible for protecting public health when emergency spills or contamination situations occur. They are not to be construed as legally enforceable federal standards. The Health Advisories are subject to change as new information becomes available.

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2007 Experts Scientific Workshop

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