Rapid assessments of recreational water quality

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Rapid assessments of recreational water quality
River Rally May 4, 2008
Donna Francy, Amie Brady, and Rebecca Bushon USGS
Ohio Water Science Center
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Todays Agenda

• Introduction to public health microbiology and
  bacterial indicators
• Recreational water quality monitoring and
  assessment
• Rapid analytical methods
• Predictive models

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Waterborne disease is a public health concern

• Pathogens ingested from
• drinking water
• recreational water
• contaminated fish or shellfish
• Potential sources of pathogens
• treated and untreated sewage
• septic tanks
• combined sewer overflows
• landfills
• animal waste

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Incidence of recreational waterborne disease
outbreaks in the US
2003-04, 62 waterborne disease outbreaks
Etiologic Agents Identified Bacteria 32.3
Protozoa 24.2 Virus 9.7 Chemical or Toxin
4.8
Centers for Disease Control and Prevention (CDCP)
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Factors effecting incidence of waterborne Illness
in the US

• Increasingly greater threat to public health
• Increase in population
• Aging water-treatment systems
• Aging population
• Inadequately managed animal wastes
• Lack of integrated regulatory approach

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Types of waterborne pathogens
Protozoa (larger, complex cells)
Viruses (tiny, non-living)
Bacteria (medium size, simple cells)
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Pathogens and swimming-associated illnesses
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Why dont we test directly for waterborne
pathogens?

• Safety
• May require direct manipulation of pathogenic
  organisms
• Time and cost
• Each pathogen must be detected using a different
  test
• Requires processing of large volumes of sample
• Pathogens usually are present in low
  concentrations

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Indicators of fecal contamination

• Indicator organisms
• usually NOT pathogenic
• "indicate" the possible presence of pathogenic
  organisms
• Used to directly detect the presence of fecal
  contamination from warm-blooded animals

E. coli
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An Ideal Indicator Organism

• Has an easy testing procedure
• Is of human or animal fecal origin
• Survives as long as, or longer, than pathogens
• Present at densities related to the degree of
  fecal contamination
• Is a "surrogate" for many different pathogens
• Useful in fresh and saline waters

Enterococci
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Indicator OrganismsProblems

• Present when there is no fecal contamination
• Total coliforms and C. perfringens are found in
  soil so they are not exclusively indicators of
  fecal contamination
• Absent when pathogens are present
• E. coli may die off faster than viral pathogens
• Density may not always relate well to the density
  of pathogens
• E. coli can reproduce in warm, tropical waters

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Methods for detecting indicators
Membrane filtration method
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Methods for detecting indicators
Enzyme substrate tests
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Tests for Escherichia coli

• Membrane filtration method
• Modified mTEC agar
• E. coli colonies are magenta colored after
  incubation.

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Tests for Escherichia coli
Enzyme substrate test Colilert E. coli positive
wells fluoresce under UV light. (Total coliforms
positive wells are yellow under ambient light.)
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Tests for Enterococci

• Membrane filtration method
• mEI agar
• Enterococci colonies have a blue halo.

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Tests for Enterococci
Enzyme substrate test Enterolert Enterococci
positive wells fluoresce blue under UV light.
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Recreational water quality monitoring and
assessment
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Definitions

• Criteria
• Are not rules and do not have regulatory impact.
• Scientific data and guidance on the potential
  human health risk involved in the waters use (or
  in acceptable limits for aquatic life).

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Definitions

• Standards
• Have regulatory impact
• Rules set forth by the state or USEPA to protect
  users of waters (based on water-quality criteria)
• For indicator bacteria, based on a quantifiable
  relation between
• density of the indicator in water
• the potential human health risk by the waters
  use

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Criteria for recreational waters
Relation between E. coli and swimming-associated
gastrointestinal illness
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Relation between fecal coliforms and
swimming-associated gastrointestinal illness
Criteria for recreational waters
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USEPA criteria for recreational waters1986
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USEPA BEACH PROGRAM

• Beaches Environmental Assessment and Coastal
  Health Act of 2000 (BEACH)
• Required the states to adopt criteria into
  standards
• Required USEPA to develop new criteria by late
  2005
• Required USEPA to address research topics such as
  modeling/monitoring, exposure and health effects
• Provided grants to the states and local
  governments to develop new monitoring programs
• Provided national beach guidance

http//www.epa.gov/beaches
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Need for rapid assessments

• At Ohio beaches, advisories are issued if E. coli
  is gt 235
• Culture results take 18-24 hours
• Water quality may change during that time

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Solutions for rapid assessments

• Rapid analytical methods
• Description of qPCR and IMS/ATP
• Rapid method studies
• Predictive models
• State of the science
• Nowcasting at Ohio beaches and a recreational
  river

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SOLUTIONS?
RAPID ANALYTICAL METHODS
MOLECULAR (qPCR)
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qPCR RAPID METHOD

• Target and amplify specific DNA sequences
• Standard curve is created from analyzing known
  quantities of target organism
• Unknown sample values are interpolated from the
  standard curve

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Field Testing of qPCR Method

• USGS and Northeast Ohio Regional Sewer District
• Samples were collected from July September 2006
  and 2007 at two Lake Erie beaches - Edgewater and
  Villa Angela
• Objective Compare results obtained by qPCR to
  those of the conventional membrane-filtration
  method

• Project funded by the Ohio Department of
  Health

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E. coli Standard Curve
y -3.5551x 44.835 R2 0.9497
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Correlations between qPCR and membrane filtration
for E. coli
r 0.825
r 0.786
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qPCR results Villa Angela 2007
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Next Steps for qPCR

• DNA extraction
• Test different extraction kits
• Analyze samples daily or weekly not in batch
  format
• qPCR
• Find alternate source for assay reagents
• Determine the best data interpretation procedure
• Transfer technology to local agencies

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IMS/ATP RAPID METHOD

• Immunomagnetic separation (IMS)
• Uses antibody-coated magnetic beads which bind to
  antigens present on the surface of cells
• Adenosine triphosphate (ATP)
• Energy molecule in all cells
• Reported in Relative Light Units (RLU)

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Field Testing and Technology Transfer of IMS/ATP
Method

• Water samples from Ohio Lake Erie beaches
• In cooperation with local and state cooperators
  (2005-2007)
• Water samples from a recreational river (CVNP)
• In cooperation with federal cooperators
  (2004-2006)
• Sewage samples from Ohio, NC, and CA plants and
  water samples from Avalon Beach, CA
• In cooperation with Southern California
  Coastal Water Research Project
  (SCCRWP)

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Correlations between IMS/ATP and membrane
filtration for E. coli
Cuyahoga River at Jaite, 2006
r0.55
r0.67
r0.89
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Villa Angela 2007 Relations to E. coli
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Next steps for IMS/ATP method

• Continue refinement of IMS/ATP
• Identify additional antibodies that include most
  strains
• Optimize the beads and reagents
• Test at other locations
• Test whether it is a stand alone method or can be
  used in existing models, integrate in predictive
  models
• Epidemiological study - SCCWRP
• Transfer technology to local agencies

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SOLUTIONS? PREDICTIVE MODELS
RAINFALL BASED ALERTS

• Stamford, Ct (20 years)
• Door County and Milwaukee, Wi
• Southern Ca (10 years)
• Delaware (12 sites)
• Myrtle Beach, SC
• Boston Harbor
• Ozaukee County, Wis
• (may use in 2008)

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SOLUTIONS?

• MULTI-VARIABLE STATISTICAL MODELS

• Linear relations between variables and E. coli
• Use statistical techniques such as multiple
  linear regression
• Beach specific models
• Does not require identification of the source

r0.56 Plt0.0001
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SOLUTIONS?

• STATISTICAL MODELS

• OPERATIONAL MODELS
• Project SAFE, IN (4 beaches, 3 yrs)
• SwimCast, Lake County, IL (3 beaches, 1-3 yrs)
• Chicago, (2 beaches, begin in 2008?)
• Nowcast, Ohio, (1 beach, 2 years)

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NOWCASTING AT OHIO BEACHES

• Rainfall
• Turbidity
• Wave height
• Lake level
• Water temp
• Wind direction
• Day of the year

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NOWCASTING AT OHIO BEACHES

• Huntington and Edgewater
• Wave height
• Turbidity
• 48 hr weighted rainfall (Airport)
• Antecedent dry days
• Radar rainfall
• Day of the year
• Lake level

Huntington, Bay Village
Output from the model is the probability that E.
coli will be gt235 CFU/100 mL Threshold
probability ranges from 27 to 32
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Edgewater wave height buoy
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Ohionowcast.info
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NOWCAST results in 2007
Edgewater, Cleveland, Ohio
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Next steps for NOWCAST

• Villa Angela and Lakeshore, Ohio
• Standard was exceeded on the majority of days
  tested
• Correct responsesModel 61-63, Current method
  73-75
• Consider using QPCR or IMS/ATP
• Huntington and Edgewater
• Improve performance of the model
• Enable real-time measurements

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Cuyahoga Valley National Park

• Cuyahoga River

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Develop predictivemodels

• IMS/ATP rapid method results
• Streamflow
• Turbidity
• Rainfall

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Environmental variables in relation to E. coli
concentrations
Pearsons r correlation coefficients (number of
samples)
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CVNP Turbidity model
2007 Data Model results vs. Actual concentrations
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CVNP Turbidity model
Jaite 2007 data
Cuyahoga Valley N.P. Resource Management Office
and Lab
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Next Steps - CVNP

• Funded projects
• Continue data collection in 2008
• Implement the models to the public
• Continue data collection in 2009 -10
• Post model results on NOWCAST website
• Outreach news releases, factsheet
• Transfer technology to NPS
• Other
• Use of real-time turbidity sensor at site

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Acknowledgements
Christopher Kephart, Erin Bertke, Robert Darner,
USGS Ohio Water Science Center Jill Lis, Cuyahoga
County Board of Health Suzanne Britt, Ann Gliha,
and Patricia Boone, Cuyahoga County Sanitary
Engineers Eva Hatvani, Mark Citriglia, Lester
Stumpe, NEORSD Mark Pfister, Lake County Health
Department, IL Richard Whitman, USGS, Porter,
IN Calum McPhail, Scottish Environmental
Protection Agency Meg Plona, Cuyahoga Valley
National Park Ohio Lake Erie Commission Ohio
Water Development Authority