The Use of Microorganisms as Ground‐Water Tracers: A Review

Microbial contamination of ground water results in numerous disease outbreaks each year. Tracing their movement in ground water is therefore essential. Bacteria, viruses, yeasts and spores have been used for this purpose and to trace underground movement of water in much the same manner as chemical tracers are used. Chemical tracers do not always reflect the movement of microorganisms in ground water. The use of certain bacteria and animal viruses is undesirable due to their pathogenic potential and difficulties in their differentiation from background, naturally‐occurring organisms. Bacterial viruses appear to be the microorganisms most suited as a microbial tracer because of their size, ease of assay and lack of pathogenicity. Bacteriophages have been used to trace ground‐water movement over distances of 1,600 meters and can be used under a variety of conditions.