Environmental factors and chemical and microbiological constituents related to the presence of virus

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Environmental factors and chemical and
microbiological constituents related to the
presence of viruses in ground water from small
public water supplies in southeastern Michigan

• In cooperation with USEPA, Office of Research and
  Development
• Donna Francy, Rebecca Bushon, Emma Luzano USGS
  Columbus
• Julie Stopar USGS Michigan
• G. Shay Fout USEPA

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OBJECTIVES

• Determine (in small public GW supplies)
• occurrence of viral pathogens and indicators
• adequacy of indicators as predictors for presence
  of viruses
• factors that affect the presence of viruses and
  indicators

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APPROACH

• 38 drinking-water wells in glacial aquifer in
  Michigan
• Each well was sampled 1 to 5 times over a
  2-year period

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APPROACH

• Water-quality samples were collected once per
  well
• majors, nutrients, boron, DO

For viruses, we filtered 2,000 liters of GW
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Viruses by cell culture

• Viruses by RT-PCR
• Enterovirus
• Reovirus
• Rotavirus
• Hepatitis A
• Norwalk

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BACTERIAL INDICATOR METHODS
Visible spectrum
Ultraviolet wavelength
Total coliforms, E. coli, and enterococci
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COLIPHAGE BY TWO METHODS
Presence/absence method
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RT-PCR QUALITY CONTROL RESULTS

• 169 regular and 32 replicate spikes
• Of 32 replicate pairs for HAV, four were not in
  agreement
• 3 were negative in one replicate and inconclusive
  in the other
• 1 was positive in one replicate and negative in
  the other
• Eight types of QC samples

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RT-PCR RESULTS (by sample)
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BACTERIAL INDICATORS AND CULTURABLE VIRUSES
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COLIPHAGE
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VIRUSES AND INDICATORS (sample results)

• Only 2 out of 11 virus-positive samples were also
  positive for an indicator
• 1 had culturable viruses and enterococci
• 1 had enterovirus by RT-PCR and total coliforms

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VIRUSES AND INDICATORS(well results)

• 9 wells were positive for viruses
• 2 wells had enterovirus and HAV on different
  sampling days
• Viruses positive wells with indicators
• 2 total coliforms
• 1 E. coli
• 1 enterococci
• 1 F-specific coliphage

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CATEGORICAL VARIABLES

• Sampling condition GW or GW and tank
• Sewage-system type
• Distance to Septic
• Type of nearest surface water
• Nitrate plus nitrite
• Ammonia plus organic nitrogen
• Chloride
• Chloride to bromide ratios

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Sewerage-system type
p 0.088
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Presence of nitrate plus nitrite
p 0.086
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CONTINUOUS VARIABLES
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Iron concentrations
p 0.062
p 0.121
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CONCLUSIONS

• Results on viruses in GW are not reproducible
• Viruses were found in 9 of the 38 wells sampled
  (23.7 percent)
• Repeat sampling at the well is needed
• Indicators were fair predictors of the presence
  of viruses in wells (5/9), but not in samples
  (2/11)
• Related variablessewerage system type, nitrate
  plus nitrite, chloride, DOC, iron

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Donna FrancyU.S. Geological SurveyColumbus, Ohio

• dsfrancy_at_usgs.gov
• 614/430-7769