AthenaES™ Projects
Coliform Enumeration in Washington, D.C. Waterways

Client:  U.S. Naval Research Laboratory
Project Size:  $58,000
Duration:  9 months

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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