Waterborne Pathogens and Human Health Program Products

Wastewater and stormwater utilities play an essential role in reducing the pathogen load to receiving waters used for recreation. Water quality monitoring helps ensure public health protection, and practical and timely sampling and analysis methods to support monitoring and to inform management decisions are essential. Water quality criteria for pathogens are commonly used by regulatory agencies to establish baselines for supporting designated uses. Such criteria also tend to drive decisions that underlie regulatory policies, priorities, and requirements that pertain to wastewater and stormwater management programs. Accurate, quantitative information and robust data sets to support the development of appropriate criteria are paramount.

WERF’s Waterborne Pathogens and Human Health Research Program has provided state-of-the-art methods, relevant and accurate data, and tools to evaluate potential human health risk from waterborne microbes. The results support wastewater and stormwater management decisions and inform the regulatory structure and implementation requirements being considered by the U.S. EPA for the 2012 ambient recreational water quality criteria. Key areas of research include rapid methods for monitoring pathogen indicators, risk assessment tools, source tracking microorganisms, and indicators in inland, tropical, and subtropical waters.


Program Highlights

The research program was conceived to fill gaps in knowledge of relationships among pathogens, indicators, and human health. Each project supplies pieces of the puzzle while as a group they provide a more comprehensive picture that includes the following:

  • Significant additions to knowledge on rapid molecular methods for monitoring pathogens and indicators.
  • Stronger tools for analysis of risk assessment to human health.
  • Evaluation of fecal source tracking methods.


    Comparative Evaluation of Molecular and Culture Methods for Fecal Indicator Bacteria for use in Inland Recreational Waters (PATH7R09)
    Julie L. Kinzelman, Ph.D., MT (ASCP), City of Racine Health Department, WI.

    This project provides guidance on where quantitative polymerase chain reaction (qPCR) may be successfully applied for monitoring of pathogen indicators, how much variability in measurement may be anticipated, assessment of inhibition, and its relationship to culture-based assays. The results find that while not appropriate for all inland water body types, qPCR could successfully be used for coastal water quality monitoring and as an analytical tool for in-house plant operation, especially when more rapid results are desirable. A companion video outlines the steps involved in integrating qPCR into a working lab. Investigator-led hands-on training workshops have introduced qPCR techniques to more than 100 laboratory technicians and beach managers.

    Video [[Pathogens_Video|qPCR in Your Lab Introduces Rapid Method for Monitoring Pathogen Indicators]].
    This video provides an overview of quantitative real-time polymerase chain reaction (qPCR) as a method for monitoring pathogen indicators in recreational waters. qPCR is a DNA-based method capable of measuring fecal indicator bacteria in ambient waters in as little as three hours and is expected to be incorporated in new water quality critria. March 2010

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    Validation of Rapid Methods for Enumeration of Markers for Human Sewage Contamination in Recreational Waters (PATH3C09)
    (Cooperately funded though WERF, Florida Stormwater Education Foundation, and Florida Department of Environmental Protection)
     Valerie J. (Jody) Harwood, Ph.D., University of South Florida

    This study compared culture-based measures of the fecal indicator bacteria to rapid quantitative polymerase chain reaction (qPCR) methods in terms of correlation and consistency of performance in various types of subtropical waters in Florida. Two human associated microorganisms, Bacteroidales HF183, and polyomaviruses JCV and BKV, were successfully used to quantitatively assess the presence of human sewage and can be employed in conjunction with either qPCR or culture methods for quantifying fecal indicators E. coli or enterococci. The approach taken in this project can serve as a template for future investigation of these and other qPCR-based methods in surface waters across the United States.

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    Quantification of Pathogens and Sources of Microbial Indicators for QMRA in Recreational Waters (PATH2R08)
    Stefan Wuertz, Ph.D, University of California, Davis.

    This project synthesized existing information and generated new data about relationships between pathogen indicators, pathogens, and source identifiers to develop a quantitative microbial risk assessment (QMRA) framework for recreational waters. The resulting QMRA characterizes the pathogens of greatest concern in discharges and provides a framework that can help managers achieve compliance with recreational water quality criteria. Agencies in California and Alaska are among those using methods developed for the project to test for conventional indicators, Bacteroidales, and pathogens.

    [[Questions_Microbes_R|Questions, Microbes, Risks and Answers:]] A WERF team is studying the role that new quantitative microbial risk assessment (QMRA) procedures can play in revisions to recreational water criteria. Progress Spring 2010.

    [[Straight_to_the_Sour|Straight to the Source:]] New research supports the development of tools that managers can use to prioritize source control and treatment programs. Progress Summer 2009.

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    Measuring Water Ingestion Among Water Recreators (PATH5R09)
    Samuel Dorevitch, MD, MPH, University of Chicago at Illinois, School of Public Health

    This research monitored 662 individuals who participated in full- and limited-contact water recreation. Self-reported ingestion rates supported by water chemistry were used to estimate rates of water ingestion. The findings provide better exposure values for microbial risk assessments of recreational water and were used in the QMRA developed in PATH2R08.

    [[Research_Gulp_Water_|Knowledge Gulp - Water Ingestion During Water Recreation]]  March 2010

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    Chicago Health, Environmental Exposure, and Recreational Study (CHEERS) (PATH1PR06)

    Samuel Dorevitch, MD, MPH, University of Chicago at Illinois, School of Public Health.
    WERF provided a peer review for this epidemiological study of 11,000 participants that evaluated the health risks of limited contact water recreation activities – motor boating, canoeing, fishing, kayaking, and rowing – on the Chicago Area Waterways System that receives treated but not disinfected wastewater. The results show that with the exception of somewhat more frequent mild eye symptoms, health risks following recreation in the Chicago system were comparable to that of other area waters. The Metropolitan Water Reclamation District of Greater Chicago utilized the results to inform the Illinois Pollution Control Board of the risk currently posed by secondary contact recreation in the Chicago Area Waterway System.


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    Canine and Microbial Source Tracking in Santa Barbara, CA (U2R09)

    Jill Murray, Ph.D., City of Santa Barbara, Water Quality Improvement Program.
    This pilot-scale project demonstrates that canine scent tracking (sewage-sniffing dogs), can provide real-time results at low cost for illicit discharge detection, such as inputs of pollution in to stormdrains. During the course of the study the dogs were able to pinpoint the previously unlocated source of raw sewage entering a storm drain network that the City of Santa Barbara was then able to repair.

    Project articles:

    [[Sewage_Sniffing_Dog_|Dogs on the Scent: Using Canine-Scent Tracking to Locate Sources of Storm Drain Contamination.]]
    The use of dogs in locating human sewage in storm drains is being tested in this new study funded under WERF's unsolicited research program. June 2010

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    Concentration Dynamics of Fecal Indicators in Hawaii's Coastal and Inland Sand, Soil, and Water during Rainfall Events (PATH6R09)
    Tao Yan, Ph.D., University of Hawaii at Manoa.
    The project monitored the concentrations of fecal indicator bacteria before and after rainfall runoff events in inland stream water and soil, beach water, and beach sand within a tropical watershed. The results demonstrate the importance of soil and sand as reservoirs of fecal indicator bacteria in these systems, and highlight the performance of an alternative indicator bacteria Clostridium perfringens. The research led to follow-up work for the Hawaii Department of Health on bacteria survival in beach sand.

    [[Sand_Trap_Researcher|Sand Trap: Researchers Investigate Sources and Transport Routes of Fecal Bacteria in Beach Sand]]. March 2009

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    Report on the Expert Scientific Workshop on Critical Research and Science Needs for the Development of Recreational Water Quality Criteria for Inland Waters (PATH4W09)
    This workshop brought together EPA, state, utility, consulting and academic experts who identified several important gaps in extrapolating marine coastal and Great Lakes beaches to report to inland waters. The recommendations from the workshop led to a WERF project (PATH7R09) and an EPA project on comparing culture-based and rapid molecular methods (primarily qPCR) for monitoring pathogen indicators in inland lakes and streams. These efforts identified specific issues, such as inhibition of the qPCR signal caused by chemicals in the water, that will need to be addressed to support the use of rapid methods in inland waters.

    [[Workshop_Report_Prio|Workshop Report Prioritizes Research Needs for Criteria Development in Inland Waters.]] July 2009

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    Other Articles

    Progress Summer 2009 Newsletter: The Pathogens Issue

    [[Swimming_Allowed|Swimming Allowed: WERF researchers are Diving into New efforts That Will Inform U.S. EPA’s Upcoming Revisions to Recreational Water Criteria. Progress Summer 2009.]]

    [[To_Blend_or_Not_to_B|To Blend or Not to Blend: New research Will Help Utilities Evaluate Whether to Blend or Employ Other Alternatives. Progress Summer 2009.]]

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    Pathogen Program Details

    • Significant additions to knowledge on rapid molecular methods for monitoring pathogens and indicators. The rapid method quantitative polymerase chain reaction (qPCR) will be included in monitoring programs at utilities and in new recreation water criteria. Analyses of its performance in a variety of inland and coastal water bodies in temperate, subtropical, and tropical regions provide guidance on where it may be successfully used. PATH 2, PATH3, PATH6, PATH 7

    • Stronger tools for analysis of risk assessment of human health. Epidemiological data are used to develop recreational water quality criteria. Limitations of these studies such as a narrow range of water body types and a focus on coastal waters were addressed. An epidemiologic study was conducted to better understand exposures and health risks of recreation on inland waters. A risk assessment framework that can characterize site-specific health risk was developed to provide decisions makers with flexibility for assessing a variety of water bodies. PATH1, PATH2, PATH6

    • Evaluation of fecal source tracking methods. Sources of contamination are often difficult to determine and not all pose equal health risk. Analyses of indicators of human and non-human contamination sources, specific human-associated genetic markers, and dogs trained to track locations of human fecal discharges support the use of these techniques in monitoring programs and risk assessment. Other research included determining the importance of tropical soil and sand as reservoirs of fecal indicator bacteria. PATH2, PATH5, PATH7, U2R09

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