Significance and Use

This test method is useful for measuring recreational water quality and chlorinated wastewaters, although it can be used for any water suspected of contamination by fecal wastes of warm-blooded animals. The significance of finding E. coli in recreational water samples, especially samples obtained from fresh recreational waters, is that there is a risk of gastrointestinal illness, directly related to the E. coli density, associated with swimming. ⁴

Since small or large volumes of water or dilutions thereof can be analyzed by the MF technique, a wider range of levels of E. coli in water can be detected and enumerated than with other methods.

1. Scope

1.1 This test method describes a membrane filter (MF) procedure for the detection and enumeration of Escherichia coli , a bacterium found exclusively in the feces of humans and other warm-blooded animals. The presence of these microorganisms in water is an indication of fecal pollution and the possible presence of enteric pathogens. These bacteria are found in water and wastewater in a wide range of densities. The detection limit of this procedure is one colony forming unit (CFU) per volume filtered.

1.2 This test method has been used successfully with temperate fresh and marine ambient waters, and wastewaters. It is the user's responsibility to ensure the validity of this test method for waters of other types.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 9.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D1129 Terminology Relating to Water

D1193 Specification for Reagent Water

D3370 Practices for Sampling Water from Closed Conduits

D3870 Practice for Establishing Performance Characteristics for Colony Counting Methods in Microbiology

D5465 Practice for Determining Microbial Colony Counts from Waters Analyzed by Plating Methods

Keywords

ambient waters; Escherichia coli ; fecal pollution; mTEC agar; recreational waters; two-step membrane filter method; wastewaters;

ICS Code

ICS Number Code 07.100.20 (Microbiology of water)

DOI: 10.1520/D5392-93R06

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ASTM D5392