Impact/Purpose:

Develop a rapid (same day), sensitive and accurate method for detecting and measuring fecal contamination of recreational water.

Description:

The current methods for measuring the quality of recreational waters were developed in the 1970's and were recommended to the States by EPA in 1986. These methods detect and quantify Escherichia coli and enterococci, two bacteria that are consistently associated with fecal wastes from warm-blooded animals. Both of these water quality indicators have been shown to be linearly related to swimming associated illness, i.e., as the water quality indicator densities increase, the illness rate increases. The concentrations of enterococci were correlated with illness in both fresh and marine waters, while E. coli concentrations correlated with illness rates in fresh water only. Because of the relationship of these microbial indicators to swimming-associated illness, they have been recommended as monitoring tools for recreational waters. However, the results obtained using the current cultural methods are not available until 24 hours after the water samples are collected. If the water is not in compliance with the standard, the risk of exposure to enteric pathogens has potentially occurred long before the quality of the water was identified as being hazardous. This shortcoming can be eliminated by developing a rapid method producing same day results, ideally in less than two hours. In this study, several new methodologies will be evaluated for detection of enterococci in recreational waters. These methodologies include a membrane filter/immunological capture method, a flow cytometric method and a nucleic acid-based method.

Record Details:

Record Type:PROJECT

Start Date:12/01/2002

Projected Completion Date:09/01/2006

Record ID: 56195

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Project Information:

Progress :Preliminary experiments designed to demonstrate the detection step of the protocol were successfully run. Enterococci bacteria trapped on a membrane filter were detected with a colorimetric system using enzyme-conjugated, enterococci-specific polyclonal antibodies. The enzyme catalyzed a color reaction that was clearly visible in several minutes.

The evaluation of the AATI flow cytometer as a rapid method for detecting indicator bacteria in water continued in FY03. A flaw in the instrument, resulting in the growth of bacteria inside the instrument, was discovered that produced significant and unacceptable background counts. Working with the manufacturer, a procedure was developed for internal cleaning of the tubing system and a Standard Operating Procedure was written for this procedure.

Working with Army contractors, an instrument designed to detect fluorescent compounds, those often associated with fecal material, was evaluated in-house for use in detecting fecal contamination in water. The results indicate that this technology is not yet sensitive enough to be of value as a rapid method for water quality testing. Another instrument has been identified for evaluation as the basis for a rapid water quality test. Training on the use of this instrument, based on the isothermal amplification of nucleic acids, has occurred and in-house evaluation is currently underway.

Relevance : In-house development of a new rapid water quality method for recreational water, which is a high priority research area for the Agency, will meet the needs stated in the Water Quality Multi-Year Plan (Long Term Goal 1), the Clean Water Action Plan, the Beach Action Plan, and the Beach Act of 2000. Use of the rapid method for compliance monitoring will facilitate the detection of contaminated recreational water in a timely manner and allow the beach managers to alert the public about the potential health hazards before exposure to unsafe water can occur.

Clients :Office of Water, Office of Science and Technology;

Project IDs:

ID Code :7002

Project type :OMIS