BacteriALERT: A Program for Monitoring and Real-time Estimation of Indicator Bacteria

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BacteriALERT A Program for Monitoring and
Real-time Estimation of Indicator Bacteria
By Stephen J. Lawrence, Atlanta, Georgia
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Background

• The project is an outgrowth of the Georgia
  Governors Green Space Initiative and former Vice
  President Al Gores Livable Communities
  Initiative
• National Park Service wanted a means to notify
  the public when indicator bacteria in the
  Chattahoochee River exceeded the USEPA criteria

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Partnerships

• Partnerships include Upper Chattahoochee
  Riverkeeper, Georgia Conservancy, Georgia EPD,
  National Park Service, and USGS

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Purpose and Scope

• Monitor total coliform and E. coli bacteria
  levels daily at three sites on the Chattahoochee
  River
• Provide easily accessible results to the public
  within 24 hours of sample collection
• Monitor turbidity in real-time and estimate
  average E. coli concentration at two sites

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Study Area

• Currently
• limited to the Chattahoochee River National
  Recreation Area

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Sample Collection Methods

• Samples are collected by employees from the Upper
  Chattahoochee Riverkeeper (an NGO) and the
  National Park Service

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Sample Collection

• Weighted sterile bottle
• Centroid of flow
• Water column from surface to near bottom
• Sample is placed on ice and transported to USGS
  office

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Bacteria Analysis

• Colilert Method by IDEXX Corp.
• Enzyme substrate using multiple cells (wells)
• Similar to the older Multiple-tube
• Method
• Uses statistical tables to determine most
  probable number of colony forming units
• Provides results in 18-20 hours

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Bacteria AnalysisFlow chart
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Bacteria Analysis

• Under visible light, cells are yellow in the
  presence of total coliform bacteria
• Under UV light, cells fluoresce blue-green in the
  presence of E. coli bacteria

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Quality Control Measures

• Ensure that the bacteria counts represent what is
  in the river
• Cleanliness and sterility during sample
  collection and processing
• Cleanliness and sterility of bottles and utensils
• Ability to track potential points of
  contamination
• Compare with other methods

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Quality Control MeasuresCleanliness and
sterility?

• Collectors and analysts wear latex or nitrile
  gloves
• Sample bottles and utensils are either used once
  and disposed or sterilized

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Quality Control MeasuresTrack potential
contamination

• Lots of sterile water are produced and analyzed
  for bacteria
• Each reagent lot is tested for bacteria
• Sterile bottles are tested for bacteria

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Quality Control measuresCompare with other
methods

• Total coliform, fecal coliform, and E. coli
  bacteria are also analyzed by membrane filtration

m-coliblue24 broth
m-FC agar
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RESULTS--Comparison of membrane filter and
Colilert methods for E. coli
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Comparison of fecal coliform membrane filtration
with E. coli Colilert
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RESULTS--Relation between indicator bacteria and
turbidity
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Real-time Estimation of E. coliEstimation
equations

• 12 months of E. coli and turbidity monitoring
  produced enough data to develop multiple
  regression equations
• Equations use turbidity and streamflow
  measurements, season, and flow regime (baseflow,
  stormflow) to estimate E. coli bacteria density
• About 81 of the variability in E. coli density
  is explained by those parameters

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Real-time Estimation of E. coliRole of
continuous monitors

• Continuous turbidity is measured using YSI
  water-quality sondes
• These turbidity measurements, streamflow, and
  current date are plugged into the estimation
  equations every 15 minutes to give a real-time
  estimate of E. coli density.
• The E. coli estimates are retrieved by a Cold
  Fusion program and posted to the BacteriALERT Web
  page

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Public Awareness Web Page(url
water.ga.usgs.gov/bacteria)
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Web Page Linksdata tables
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E-Mail Alert

• Each day an email containing the previous days
  bacteria counts is sent to those who have signed
  up on the web page to receive the notice

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Public Awareness National Park Service On-site
Signage
E. Coli count above 235 cfu/100 mL
E. Coli count below 235 cfu/100 mL
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Public Awareness Print Media

• Several news articles have been written about
  BacteriALERT

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Public Awareness-Other

• Links to the BacteriALERT web page are found on
  the web sites and in newsletters of fishing
  clubs, conservation organizations, canoeing and
  rafting organizations