Final Report: Data Collection and Modeling of Enteric Pathogens, Fecal Indicators and Real-Time Environmental Data at Madison, WIEPA Grant Number: R829339
Title: Data Collection and Modeling of Enteric Pathogens, Fecal Indicators and Real-Time Environmental Data at Madison, WI
Investigators: Schneider, Tommye , Corsi, Steve , Sorsa, Kirsti K. , Standridge, Jon H. , Waschbusch, Rob
Institution: Madison Department of Public Health , United States Geological Survey [USGS] , Wisconsin State Laboratory of Hygiene
EPA Project Officer: Hiscock, Michael
Project Period: October 1, 2001 through September 30, 2003
Project Amount: $352,000
RFA: Environmental Monitoring for Public Access and Community Tracking (EMPACT) (2001) RFA Text | Recipients Lists
Research Category: Environmental Statistics , Water , Ecosystems , Air , Ecological Indicators/Assessment/Restoration
Beach Monitoring in Madison, Wisconsin
The overall objective of the comprehensive beach water quality monitoring program at three Madison lakes was to improve tools to identify early indicators of health risks from pathogenic organisms and help define beach conditions through data-based decisionmaking. The goal was to collect relevant, high-quality environmental data and deliver it to the public as rapidly as possible. This research project focused on the application of innovative environmental monitoring tools to determine changes in water quality that may result in adverse health effects to those who rely on these resources for recreation. The specific objectives of this research project included the following:
• Expansion of the current city recreational beach monitoring program to develop data-driven criteria for beach closures by evaluating a combination of rapid and sensitive tests for the detection of microbial indicators and pathogenic microorganisms.
• Development of a rapid and sensitive method for the detection of pathogenic Escherichia coli 0157:H7.
• Application of coliphage genotyping to determine the source of fecal contamination.
• Application of sensitive tests for the detection of pathogens responsible for enteric illness: Giardia, Cryptosporidia, Salmonella, and E. coli 0157:H7.
• Determination of the correlations between: (1) existing environmental monitoring parameters; (2) occurrence of pathogens; and (3) meteorological, physical, and water quality data collected by remote automated monitoring stations.
• Consideration of mathematical constructs for modeling pathogen occurrence.
• Development of innovative partnerships with community groups and agencies to facilitate dissemination of water quality data and beach closure decisions.
• Construction of a water quality database with dynamic query capability for ready access to the public.
• Partners from city, state and federal governments and the community worked together to focus on the issue of detecting and communicating health risks associated with swimming at Madison beaches.
• The study focused on: (1) developing and applying innovative environmental monitoring tools for the detection of emerging pathogens and novel microbial indicator microorganisms combined with real-time monitoring of environmental conditions; and (2) developing an effective communication infrastructure for dissemination of data to the public. The project provided an enhanced ability to provide real-time, user-friendly, state-of-the-art water quality information to the public.
• A large database of indicator and pathogen occurrence at inland beaches serving a major population center in the Northern Midwest was created. The collected data were loaded into Progress and Oracle databases. The continuously monitored data were made available on the World Wide Web within 1 hour of collection, and the microbial indicator data were made available following the completion of the analyses. The remaining microbiological analysis results were included on the Web after the analysis results were finalized.
• Additional pages educate and explain the significance of the collected data to the public.
• Changes in water quality information were disseminated via media, beach signs, and a telephone hotline.
• A new sensitive analytical method for detecting E. coli 0157:H7 in recreational waters was developed, modified, and implemented. The usability of the method was evaluated.
• Public education regarding recreational water quality issues was accomplished by poster presentations (at the city-county office building and lakeside), by informational materials on the Web, during neighborhood fairs, and through neighborhood newsletters and the display of information in a kiosk at the beach.
• Quantitative relationships between microbial indicator data; occurrence of pathogens; and meteorological, physical, and water quality data were sought to create a predictive model for real-time assessment of the risk of pathogen occurrence and beach closure decisions. The modeling effort showed that none of the indicators was able to represent the presence or absence of pathogens. The bacterial indicator densities, however, showed a strong statistically significant association with some environmental parameters. The predictive model used real-time environmental data as predictors for bacterial densities when they exceeded the closure limits.
Monitoring stations at each of the three beach sites continuously measured and recorded air temperature, precipitation, water temperature, turbidity, specific conductance, pH, dissolved oxygen and chlorophyll content, wave height, and water level. An additional monitoring site measured solar radiation, wind speed, and direction. The data being collected were loaded into both Progress and Oracle databases. The continuously monitored data were made available on the World Wide Web within 1 hour of collection, and the microbial data were available after the results were finalized.
Beach personnel collected samples for indicator organisms five times per week (weekdays) and three weekends during the swimming season; E. coli O157:H7 and coliphage samples were collected three times per week; and Cryptosporidium, Giardia, and Salmonella once per week using beach sampling standard operating protocol. Additionally, beach personnel monitored bather loads and bird populations.
Automatic samplers at each site were modified specifically for microbial sample collection and were programmed to collect samples during periods when selected environmental conditions experienced high short-term variability. A total of 12 event collections were conducted on each of the 3 study beaches based on high rainfall, turbidity, wind speed/wave height, or anticipated bather count.
Indicator Microorganisms and Pathogens
Pathogens. A sensitive method for detecting E. coli O157:H7 was developed and implemented. Multiple spikes into complex lake water samples confirmed the sensitivity of the assay down to 10 organisms/500 mL. Only one of multiple presumptively positive samples resulted in confirmation by culture. The remainder of the samples produced serologically and biochemically atypical reactions. The finding raised questions regarding the identification and pathogenicity of the detected organism. Clearly, additional work is needed to assess the significance of the findings. Consequently, to assure safe water quality and minimize public health risks, the laboratory will continue evaluating and refining the analytical method to understand any methodological uncertainties and the public health consequences of the potentially pathogenic isolate.
Salmonella testing was performed using the concentration, enrichment, and selective growth techniques followed by serological testing methods. Cryptosporidia and Giardia were enumerated using modified established performance-based methods.
Pathogens were detected in 37 percent of the samples collected during the Madison study. Cryptosporidium was detected in 19 of 105 samples collected during this study. The range of concentrations from these Cryptosporidium-positive samples was between 32.3 and 400 oocysts/100 L. Giardia was detected in 23 of 105 samples collected with a range of concentrations from 29.4 to 333 cysts/100 L. Of the 102 samples tested, only 7 were positive for Salmonella, concentrations of all but 1 were 10 MPN/100 mL or less, and 4 of them were detected at 0.1 MPN/100 mL.
Male-specific coliphage was analyzed using a performance-based U.S. Environmental Protection Agency (EPA) Method to distinguish between human and animal fecal contamination sources. The levels of coliphages detected were low at all beaches. The F+ RNA coliphage serotyping results indicated a potential for multiple fecal contamination sources.
Indicator Bacteria. The membrane filter fecal coliform count was used to analyze for fecal coliform. A commercial, enzyme-based Colilert Quanti-tray™ (IDEXX) assay was used for determining E. coli counts. Enterococci counts were determined using Enterolert™ test system.
All indicator bacteria exhibited a great deal of temporal and spatial variability. The maximum bacteria levels were short lived, normally lasting less than a day at their highest levels and frequently coinciding with rainfall and high wave periods. The peaks and valleys of the bacterial populations generally followed the same pattern with differences in magnitudes within different organisms and different beaches.
Public Access to Project Data
The primary method of getting the data to the public was using Web pages, but other means also were employed. Beach water quality information was distributed to radio and TV stations, newspapers, and onsite signs. A telephone hotline of current beach conditions or other inquiries was available to the public. Friends of Lake Wingra and the University Extension Environmental Health Office also disseminate the data through public outreach activities.
Regression models were developed for prediction of E. coli concentrations. These models predict indicator bacteria levels using environmental variables that can be monitored in real time. Using these models and the real-time environmental data, time-relevant decisions regarding beach closures can be made. Using the historical Madison beach closure criteria of E. coli greater than 1,000 MPN/100 mL, the environmental variables used in the model are specific conductance, significant wave height, and 3-hour antecedent precipitation. Using the U.S. EPA beach guidance value of E. coli concentration greater than 235 MPN/100 mL, several different environmental variables are used in the model, including specific conductance, water temperature, significant wave height, wind speed and direction, air temperature, erosivity index, antecedent precipitation, and solar radiation.
This research project did not uncover useful predicting capabilities for pathogen occurrence using indicator results. The relatively low occurrence of pathogens detected during this study suggests that additional monitoring may be required to establish statistically significant relationships.
During the swimming season, continuously monitored water quality, meteorological, and physical data from the U.S. Geological Survey (USGS) monitoring stations were retrieved via modem each hour and made available through the World Wide Web within 10 minutes of retrieval. The Web presentation included graphs of each individual parameter for the previous 7 days, although users could retrieve data from the past 31 days if desired. Current environmental data at the monitoring stations were available during the swimming season at the USGS Web Site.
The Friends of Lake Wingra (FOLW) published articles describing the project in neighborhood newsletters in the Lake Wingra Watershed. The articles reached over 7,000 households. The FOLW developed bilingual (English?Spanish) kiosks that were placed at the beach. The kiosks presented educational information on the EMPACT project as well as on other watershed topics.
During the National Water Monitoring Day, October 18, 2002, that celebrated the 30th anniversary of the Clean Water Act, the project partners publicized and organized beach monitoring activities on one of the EMPACT beaches. The event included a poster presentation on beach health as well as demonstrations of water monitoring and sampling equipment.