Indicators and Alternate Indicators of Growing Water Quality

Abstract

The coliform group of indicator bacteria has traditionally been the basis for the microbiological growing area standard for shellfish waters since the early 1900s. Since that time researchers have identified deficiencies in its use as an indicator of fecal contamination or potential health risk in aquatic systems (e.g., Berg 1978; Cabelli 1978b; Dutka 1973). Responses to these criticisms are evident in a measured progression to adopt the most fecal-specific coliform organisms as approved indicators. Thus, the fecal coliform has supplanted the total coliform group, and eventually, Escherichia coli may replace the fecal coliform. However, recent studies challenge the fundamental assumption that E. coli is a valid predictor of enteric disease in marine waters (Cabelli et al. 1983). Other workers have identified processes whose effects on indicator densities seriously question the validity of the coliform group as the basis for the growing water standard.