Water: Drinking Water Standards
Table 1: Microbial Monitoring under GWDR: possible indicators
|Organism||Density in raw sewage||Occurrence in human stools||Survival in environment||Lab Availability||Association with fresh fecal contamination|
|total coliforms||>109/L||100%||Weeks to years||Excellent||Indirect|
|E. coli||109/L||100%||Weeks to months||Excellent||Good|
|Enterococci||107/L||100%||Weeks to months||Excellent||Good|
|106/L||100%||Months to years||Potential good||Fair|
|Somatic coliphage1||106/L||50%||Weeks to months||Potential good||Good?|
|Male-specific coliphage1||106/L||<5%||Weeks||Potential good||Good|
|50-250+ PFU/L in U.S.||---||Weeks to months||Potential fair||Good|
1Coliphage are viruses that infect the bacterium, E. coli.
2Enteroviruses include polioviruses, coxsackieviruses, and echoviruses. PCR (polymerase chain reaction) is a process to multiply the number of a specific DNA or RNA strands, allowing easier detection by a variety of methods. PCR must be combined with other processes, such as sample filtration, filter elution, sample purification, perhaps tissue cultures, and assay procedures (e.g., genetic probes).