E' coli Facts Beach Monitoring

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E. coli Facts Beach Monitoring

• Julie Kinzelman, City of Racine
• Beach Management Workshop
• April 14 15, 2005, Egg Harbor, WI

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USEPA BEACH Act of 2000

• States having coastal recreational waters must
  adopt new/revised water quality standards
• Must use approved indicator organisms E. coli
  or enterococci
• Must use approved testing methods mTEC or
  modified mTEC agar, Colilert, Colisure
• Prompt public notification

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Approved Indicator Organisms

• E. coli or enterococci

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What is an Indicator Organism?

• Found in feces of humans and other animals
• Act as a warning that human pathogens may be
  present
• SURROGATES for pathogenic micro-organisms
• NOT pathogens
• Provide no information about source of
  contamination

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Why not just test water for pathogens?

• Too many possibilities Salmonella, Shigella,
  Campylobacter, viruses
• Too slow.
• Too expensive.

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What makes a good indicator?

• Their density in water (without proliferation)
  gives a reasonable estimate of pathogen presence
  and can be positively correlated with the
  potential health risks associated with exposure
• Their presence is consistently and exclusively
  associated with the source of the pathogens
• Their ability to demonstrate similar resistance
  to environmental stress as the most resistant
  pathogens present at significant levels
• Their constant characteristics provide for
  accurate quantification which can be achieved
  through simple and inexpensive detection methods
• Their presence must be harmless to humans and
  animals
• Their ability to be detected by laboratory
  methods in the shortest amount of time consistent
  with providing accurate results (WHO 1997)

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E. coli

• Normal intestinal flora of humans and animals
  (about 0.1 of humans)
• Member of the fecal coliform group
• Fresh water quality standard

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Advantages/Disadvantages

• High numbers have been associated with an
  increased frequency of GI illness in bathers
• Simple and inexpensive to detect
• Can get results in less than 24-hours
• Present in high number in non-human sources such
  as seagulls
• If environmental persistence or replication
  occurs it may lack relevance

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Sample Collection

• Racine, WI

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Surface Water Sampling

• Fixed monitoring stations
• Fixed sampling frequency
• Sampled at same time each day
• Collected at consistent depth
• Record ambient conditions

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Racine Sampling Protocol

• One station every 200m
• Monitored M F (more if advisory/closure)
• Samples collected between 1130 1300
• Collected at a depth of 3 ft _at_ 1 ft below surface
• Record ambient conditions (air/water temp, wave
  height, wind speed/direction, rainfall, bathers,
  gulls, algae, and other notables)

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Testing Protocol

• Approved Methods (Racine)

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Membrane Filtration

• M-TEC or modified m-TEC agar
• Results available in approximately 24 hours
• Good technique if you will be using the results
  for source tracking
• Requires personnel trained in microbiology
• Labor intensive
• Plates can be overcrowded if not diluted properly

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E. coli using MF/m-TEC agar
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E. coli colonies on m-TEC
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Chemical Substrate Tests

• Colilert, Colilert-18, Colisure
• Results in as little as 18 hours
• Would require plating to additional media for
  source tracking
• Easy to use
• Requires little hands on time
• Can quantify up to 2419.2 MPN/100 ml without
  diluting
• Less interference from background organisms

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E. coli using Colilert-18
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E. coli Life Cycle

• Persistence or replication may influence
  monitoring results

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Sources of E. coli

• Storm water discharge
• Sanitary systems
• Algae
• Animal feces

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E. coli in Sand (Whitman, 2002)
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Poor Estimation of Health Risk

• Type I errors occur when an advisory is posted
  but the level of bacterial indicator organisms do
  not exceed recommended standards or guidelines
• Type II errors occur when no advisory is posted
  in the presence of elevated bacterial indicator
  levels

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Racine Data 2002 - 2004
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Whats on the Horizon?

• Alternative indicators
• Real-time testing technology
• New epidemiological studies (USEPA)
• Pathogen studies
• Research designed to determine replication/persist
  ence and host source of bacterial indicators

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Acknowledgements

• WI DNR
• Richard Whitman, USGS
• UWM Great Lakes Water Institute
• S.C. Johnson, A Family Company
• City of Racine Health Department
• University of Surrey, RCPEH