Task 5: Identify new methods
Task Chief: Donna Francy
Collaborators: Northeast Ohio Regional Sewer District; Cuyahoga County Board of Health; Cuyahoga County Sanitary Engineers; Erie County Health Department; Ohio Department of Health
Period of Project: March 2008 - present
Student processing a sample by the IMS/ATP (immunomagnetic separation/adenosine triphosphate) rapid method.
Task 5 long-term goals
The long-term goal of task 5 is to test and modify analytical methods that can be used by others to monitor water quality and investigate microbiological processes at coastal beaches. These include rapid analytical methods for bacterial indicators, methods to determine the dynamics of bacterial populations in sand and water, microbial and chemical source tracking methods, and methods to determine concentrations of pathogenic microorganisms.
Objectives
Test microbiological methods at Great Lakes beaches to identify methods that provide useful data for addressing the long-term goals. Specific objectives are to:
- Test rapid analytical methods for bacterial indicators to determine if the relation between the rapid method and the standard method remains consistent in water collected from a variety of different beaches.
- Evaluate the utility of applying a rapid method for determining bacterial indicator concentrations on multiple beaches and analyzed by a central laboratory.
- Compare the relative performance of the traditional membrane filtration (MF) and published QPCR methods for enterococci or E. coli measurements on different surface water and sediment samples.
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Samples are prepared in the laboratory for analysis by QPCR (quantitative polymerase chain reaction).
Evaluate several analytical methods for their ability to resolve differences in indicator bacteria community composition among a variety of beach-water samples.
Approach
- Select analytical methods. Candidate analytical methods include the following:
- QPCR bacterial indicators.
- Immunomagnetic separation/adenosine triphosphate (IMS/ATP) for E. coli and enterococci
- E. coli phylotyping
- Terminal restriction fragment length polymorphism (T-RFLP)
- Pathogen and microbial source tracking methods
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A luminometer is used to determine relative light units (RLU) of adenosine triphosphate (ATP) in samples by the IMS/ATP (immunomagnetic separation/adenosine triphosphate) rapid method.
Site visits and selection. Work at several Ohio beaches along the western Lake Erie shoreline, several beaches in northwest Indiana, and other locations. Ohio beaches along the western shoreline were selected because they are relatively close to other participating WSCs, would enable collaborations with new local partners, and provide a variety of land-use settings and contaminant sources. The Indiana study sites were selected because of the availability of historical data, variety of water/sediment types, and potential relationship to other tasks in the project. Site visits will be scheduled to view and select beaches.
- Develop study design. Decide on sampling and analytical methods and frequency and finalize study design during site visits and in follow-up conference calls.
- Perform preliminary method modification and testing, including the following:
- In the Ohio WSC, develop the capability for enterococci by QPCR. This includes quantifying primers and probes, establishing a standard curve, and testing washed versus unwashed cell preparations for development of the standard curve.
- In Indiana at the GLSC, conduct pilot studies to compare how membrane filtration and QPCR methods perform in measuring enterococci or E. coli densities in water and sediment samples.
Method for enumeration of fecal indicator bacteris (FIB) in sand
- Data collection, sample analysis, and data management.
- Sampling at Ohio beaches will be done once/week (every Tuesday) and after four rainfall events. Weekly samples will be collected by local agencies and shipped overnight to the Ohio WSC. Rainfall-event samples will be collected by the Ohio WSC.
- In the Ohio WSC, samples will be processed for subsequent analysis by QPCR and analyzed for E. coli and enterococci by IMS/ATP and by standard plating methods. The Ohio WSC will analyze samples for E. coli, enterococci, and general Bacteroides by QPCR.
- In Indiana, weekly water and sediment samples will be collected at the study sites. How matrix characteristics, including turbidity, organic matter content, color and textural composition, influence enterococci or E. coli measurements will be evaluated on selected sub-samples.
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