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AthenaES™ Projects
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Coliform Enumeration in Washington, D.C. Waterways
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Client: U.S. Naval Research Laboratory
Project Size: $58,000
Duration: 9 months
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Several waterways in and around the Washington, D.C. area have been suspected
of being contaminated with coliform bacteria. This class of bacteria presents
a serious human health concern if present in high levels. To establish the
seasonal level of this class of bacteria, a study was initiated to examine
the physical, chemical and biological properties of the Potomac River (3
stations), Anacostia River (6 stations) and Rock Creek (7 stations).
AthenaES?s portion of the project entailed determining the level
of coliform bacterial contamination in environmental samples taken at weekly
intervals over 9 months from each waterway. Samples were analyzed according
to the Multiple-Tube Fermentation Technique for Members of the Coliform Group,
using Protocol for Microbial Examination #9221. The samples were analyzed in
three stages, with all samples first tested using the Presumptive Phase of
technique 9921B. Positive/negative results along with the most probable number
(MPN) of coliform bacteria on positives were reported. Positive samples were
then tested in the Fecal Coliform Procedure 9221E. MPN values were determined
and positive samples tested using the Escherichia coli Procedure 9221F to
determine the MPN of E. coli bacteria. Preliminary analysis of the data has
shown coliform counts ranging from a low of not detectable to well over 20,000
per 100 ml. Fecal coliform counts were as high as 5,000 per 100 ml. The number
of bacteria appeared to increase in direct correlation with storm events as well
as increased water temperatures. Final analysis of the data is pending with the
conclusion of the project.
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