Use of Baker's Yeast to Trace Microbial Movement in Ground Water

Field and laboratory tests were made using suspensions of baker's yeast ( Saccharomyces cerevisiae ) to trace movement of microbes in artificially recharged ground water. Yeast cells penetrated more than 7 meters into a sand and gravel aquifer in less than 48 hours. It is believed that most of the cells travelled through channels formed by the solution of calcium carbonate rather than through intergranular pores. Ease and sensitivity of detection, coupled with negligible background correction, suggest that baker's yeast is an excellent choice as a tracer for this type of application.