USE OF COLIFORM BACTERIA IN ASSESSING HUMAN SEWAGE CONTAMINATION

The presence of coliform bacteria in water bodies traditionally has been used as an indicator of human fecal contamination. Total coliforms, fecal coliforms (Escherichia coli), and fecal streptococci are the most commonly used bacteriological indicators. A positive correlation between these pollution indicators and fecal contamination from warm-blooded animals has been repeatedly demonstrated. Despite the usefulness of these indicator species, false conclusions can be drawn if results are not carefully interpreted. The advantages and limitations of these indicator species used alone and in conjunction with other water quality indices are reviewed using research by the authors as case examples.