ASTM D6734-01(2009)

1.1 This test method covers the determination of coliphages infective for E. coli C in water. The test method is simple, inexpensive, and yields an indication of water quality within 6.5 h. This coliphage method can determine coliphages in water down to 1 coliphage per volume of water sampled.

1.2 The test method is applicable to natural fresh water samples and to settled, filtered or finished water samples.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 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.
Significance and Use:

Coliphage organisms may serve as indicators of fecal contamination. The presence of coliphages in water in the absence of a disinfectant indicates the probable presence of fecal contamination. The absolute relationship between the number of coliforms and coliphages in natural waters has not been conclusively demonstrated. Coliphages are generally more resistant than coliforms to chlorination and may have some advantage over coliforms as an indicator of treatment efficiency in disinfected waters. The detection of coliphages in a water sample depends upon the use of a sensitive host strain in the coliphage assay. Coliphages may be detected by this concentration procedure in 6.5 h to provide important same-day information on the sanitary quality of water. The lower detection limit of this concentration procedure is 1 coliphage per volume of water sample tested.