Coliform organisms Elvire Jacques, MD Environmental health

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Coliform organismsElvire Jacques,
MD Environmental health
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Safe Drinking Water Act (SDWA)

• 1974
• EPA regulates contaminants which may be health
  risks and which may be present in public drinking
  water supplies.
• Revisions 1986, 1996

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Microbial indicator of fecal contamination

• Always found in warm-blooded animal feces
• Greater number than pathogens
• Cannot multiply in water
• Simple, reliable identification tests
• Increased resistance to disinfectants
• Dutka, Jrnl Environmental Health 3639-46,1973

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Coliform organisms

• Gastrointestinal tracts of humans and animals
• Harmless

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• Different species
• Escherichia coli
• Klebsiella species
• Enterobacter species
• Citrobacter species
• Proteus species
• Misc.

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EPA health goal

• Total coliforms zero

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Legal limit on total coliforms

• Systems must not find coliforms in more than 5
  of monthly samples to meet EPA's standards.
• If more, report violation to the state and the
  public

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Contaminant MCLG (mg/L) MCL or TT (mg/L) Health effects Source
Cryptosporidium 0 TT GI illness Human and animal feces
Giardia 0 TT GI illness Human and animal feces
Legionella 0 TT Legionnaires disease water
Total coliform (fecal colif and E. coli 0 5 Presence may indicate other harmful bacteria Environment Fecal colif. and E. coli from human and animal feces
Viruses (enteric) 0 TT GI illness Soil runoff
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• The presence of coliform bacteria in tap water
  suggests that the treatment system is not working
  properly or that there is a problem in the pipes

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Contamination, then what?

• Repair the disinfection/filtration equipment
• Flush or upgrade the distribution system
• Enact source water protection programs to prevent
  contamination.

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Total coliform positive

• Repeat samples within 24 hours
• Analyze for fecal coliforms and Escherichia coli
  (E. coli)
• Positive fecal coliform
• MCL violation
• State and public notification because of direct
  health risk.

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Water Treatment Agents

• Chlorine
• Ozone
• Sun
• Filtration systems

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Ozone treatment
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Water treatment plant
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Thank you