Abstract
Bacteria are important in the assessment of water quality because certain organisms may be used as indicators of pollution of various types, and because bacteria possess diverse metabolic capabilities that bring about the mineralization of substances, many of which other organisms are unable to use. The limitations of the widely used coliform procedures are discussed and some new approaches to the detection of organisms of fecal origin are presented. Methods for determining bacterial biomass are presented. However, measures of bacterial activity are more desirable because it is activity that will affect water quality. Some recent approaches to the measurement of bacterial growth and metabolism directly in natural habitats are presented.