AWWA PATH50776

The US Environmental Protection Agency is proposing that water utilities monitor for aeromonads in distribution system water as part of the Unregulated Contaminant Monitoring program. This study provides a validated method for this monitoring program. Samples were analyzed from a variety of potable waters, including tap, well and cistern waters, using the membrane filter recovery medium. Aeromonads should produce yellow colonies on this medium. Of 13 aeromonas species tested, all but three were able to grow on ampicillin-dextrin agar at both 30 and 35C and produce yellow colonies. Samples of potable water from the Ohio, Indiana and Kentucky tristate area were also analyzed but no bacterium was isolated from 40 tap water sources. Aeromonads were found, in 80% of the wells tested (16/20) and in 60% of the cisterns (6/10). Individual yellow colonies were collected and identified: 80% were aeromonas, 10% vibrio and 13% other genera. Future research plans include the identification of aeromonads found in well and cistern waters. Includes 15 references, tables.