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Rapid assessments of recreational water quality

Rapid assessments of recreational water quality. River Rally May 4, 2008. Donna Francy, Amie Brady, and Rebecca Bushon USGS Ohio Water Science Center. Today’s Agenda. Introduction to public health microbiology and bacterial indicators Recreational water quality monitoring and assessment

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Rapid assessments of recreational water quality

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

  2. Today’s Agenda • Introduction to public health microbiology and bacterial indicators • Recreational water quality monitoring and assessment • Rapid analytical methods • Predictive models

  3. 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

  4. 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)

  5. 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

  6. Types of waterborne pathogens Protozoa (larger, complex cells) Viruses (tiny, non-living) Bacteria (medium size, simple cells)

  7. Pathogens and swimming-associated illnesses

  8. Why don’t 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

  9. 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

  10. 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

  11. Indicator Organisms—Problems • 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

  12. Methods for detecting indicators Membrane filtration method

  13. Methods for detecting indicators Enzyme substrate tests

  14. Membrane filtration method Modified mTEC agar E. coli colonies are magenta colored after incubation. Tests for Escherichia coli

  15. 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.)

  16. Membrane filtration method mEI agar Enterococci colonies have a blue halo. Tests for Enterococci

  17. Tests for Enterococci Enzyme substrate test Enterolert Enterococci positive wells fluoresce blue under UV light.

  18. Recreational water quality monitoring and assessment

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

  20. 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 water’s use

  21. Criteria for recreational waters Relation between E. coli and swimming-associated gastrointestinal illness

  22. Criteria for recreational waters Relation between fecal coliformsand swimming-associated gastrointestinal illness

  23. USEPA criteria for recreational waters—1986

  24. 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

  25. Need for rapid assessments At Ohio beaches, advisories are issued if E. coli is > 235 Culture results take 18-24 hours Water quality may change during that time

  26. 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

  27. SURFACE RECOGNITION (IMS/ATP) SOLUTIONS? RAPID ANALYTICAL METHODS MOLECULAR (qPCR)

  28. Unknowns 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

  29. 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

  30. E. coli Standard Curve y = -3.5551x + 44.835 R2 = 0.9497

  31. Correlations between qPCR and membrane filtration for E. coli r = 0.825 r = 0.786

  32. qPCR results – Villa Angela 2007

  33. 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

  34. M A G N E T 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)

  35. 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)

  36. Correlations between IMS/ATP and membrane filtration for E. coli Cuyahoga River at Jaite, 2006 r=0.55 r=0.67 r=0.89

  37. Villa Angela 2007: Relations to E. coli

  38. 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

  39. 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)

  40. 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 r=0.56 P<0.0001

  41. 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)

  42. NOWCASTING AT OHIO BEACHES • Rainfall • Turbidity • Wave height • Lake level • Water temp • Wind direction • Day of the year

  43. 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 >235 CFU/100 mL Threshold probability ranges from 27 to 32%

  44. Edgewater wave height buoy

  45. Ohionowcast.info

  46. NOWCAST results in 2007 Edgewater, Cleveland, Ohio

  47. Next steps for NOWCAST • Villa Angela and Lakeshore, Ohio • Standard was exceeded on the majority of days tested • Correct responses—Model 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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