Distribution comparison between coliphages and phages of anaerobic bacteria (Bacteroides fragilis) in water sources, and their reliability as fecal pollution indicators in drinking water

Abstract

E. coli somatic and male specific bacteriophages and Bacteroides fragilis bacteriophages had been surveyed in drinking water for three years. Concurrently, coliforms and fecal coliforms bacteria were also measured. Occasionally several large drinking water volumes were tested for enteric viruses and the above bacteriophages. Sampling site cluster shows good correlation between bacteriophages and bacterial indicators, as pollution index. Water from the three main supply sources showed increased bacteriophage presence as follows: well > lake >spring. Mixture of the three water supplies revealed different contamination frequency. Bacteriophages' presence in drinking water presumably points to contamination of these sources. Results of a different study on groundwater aquifer recharged with reused water, and retained for more than 20 months before being drawn out, showed absence of these bacteriophages. The current results correlate with other studies, indicating that filtration is a necessary step in water treatment. With the introduction of full scale filtration units in the near future, it is expected to find a decline in the presence of these bacteriophages in drinking water in Israel. Following additional studies, use of suggested E.coli bacteriophages of type male-specific (F+) similar to coliforms and B.fragilis bacteriophages to fecal coliforms as pollution index of drinking water, in addition to classical indicators.