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ESCHERICHIA COLI: THE BEST BIOLOGICAL DRINKING WATER INDICATOR FOR PUBLIC HEALTH PROTECTION
Citation:
Edberg, S. C., E W. Rice*, R. J. Karlin, AND M. J. Allen. ESCHERICHIA COLI: THE BEST BIOLOGICAL DRINKING WATER INDICATOR FOR PUBLIC HEALTH PROTECTION. JOURNAL OF APPLIED MICROBIOLOGY 88(S6):106S-116S, (2000).
Description:
Public health protection requires an indicator of fecal pollution. It is not to analyze drinking water for all pathogens. Escherichia coli is found in all mammal feces at concentrations of 10 log 9/gram. It does not multiply appreciably in the environment. In the 1890s, it was chosen as the biological indicator of water treatment safety. Because of method deficiencies, E. coli surrogates such as the 'fecal coliform" and total coliforms tests were developed and became part of drinking water regulations. With the advent of the Defined Substrate Technology in the late 1980s, it became posible to inexpensively and simply analyze drinking water directly for E. coli (and, simultaneously, total coliforms). Accordingly, E. coli was re-inserted in the drinking water regulations. E. coli survives in drinking water for between 4 and 12 weeks, depending on environmental conditions (temperature, microflora, etc.). Oxidant resistant tracks bacteria and viruses, but is less than parasite cysts. Under the conditions in distribution systems, E. coli will be much more long-lived. Therefore, under most circumstances it is possible to design a monitoring program that permits public health protection at a modest cost. Drinking water regulations currently require infrequent monitoring which may not adequately detect intermittent contamination events; however, it is cost-effective to markedly increase testing with E. coli to better protect the public's health. Comparison with other practical candidate fecal indicators shows that E. coli is far superior overall.