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Evaluation of Freshwater Uses and Bacteria: Different Pathogen Indicator?. What is our goal?. Reasonable and realistic protection for recreational uses of freshwaters. What makes a good Pathogen Indicator?. Indicator predicts illness rates due to ingestion of water by swimmers

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what is our goal

What is our goal?

Reasonable and realistic protection for recreational uses of freshwaters

slide3

What makes a good Pathogen Indicator?

  • Indicator predicts illness rates due to ingestion of water by swimmers
  • Indicator is specific to sewage or fecal sources
what do we currently test for
What do we currently test for?
  • Fecal coliform bacteria have been considered an indicator that mimics the pathogens of concern
  • When fecal coliform bacteria are present, it is possible that other organisms that can make us sick are present too
why are we considering changing the pathogen indicator now
Why are we consideringchanging the pathogen indicator now?
  • Advancements in science & technology now allow for pathogen indicators more specific to fecal sources
  • EPA has recommended states stop using fecal coliforms as an indicator and adopt a new indicator
what does epa advise now
What does EPA advise now?
  • Enterococcus
    • Saltwater or freshwater
    • Mimics the pathogens of concern
    • However, may have non-fecal sources (plants and insects)
  • E. coli
    • Freshwater only
    • More specific to sewage or fecal sources
current epa advice based on
Current EPA advice based on:
  • Occurrence of illness (occurrence of gastroenteritis, or upset stomach, nausea, diarrhea)
  • Both of the suggested alternative indicators showed much stronger correlations with the occurrence of illness than fecal coliforms
how do we do it
How do we do it?
  • Water classifications and standards
    • Define beneficial uses to be protected (like swimming)
    • Set numeric instream values to protect uses
  • Monitoring
    • Compare data to standards
what do we mean by recreational uses
What do we mean by Recreational Uses?
  • Recreation with intentional frequent full body immersion (e.g. swimming beaches, water skiing, scuba diving, other whole body water-contact sports, etc., a.k.a. Primary Contact Recreation)
  • Recreation with a low probability for total body immersion or ingestion of waters (e.g. wading, boating, fishing, etc., a.k.a. Secondary Contact Recreation)
the intent is reasonable and realistic protection of recreational uses of freshwaters
The intent is reasonable and realistic protection of recreational uses of freshwaters
  • Identify the waterbodies of the state regularly used for primary contact activities (like swimming)
  • Provide the highest level of protection to these waters
  • Focus diminished resources on meeting standards in these waters
  • Determine reasonable protection for waterbodies used less frequently for full body contact activities
what has been done so far
What has been done so far?
  • In 2009, collected weekly samples for fecal coliforms, Enterococcus, and E. coli statewide
  • Sites included streams and lakes in a range of sizes
  • Research other state’s programs
number of samples analyzed
Number of Samples Analyzed
  • Started with 74 sites
  • 10,922 total analyses
    • 3,717 fecal coliform bacteria
    • 3,602 E. coli
    • 3,603 Enterococcus
censored data
Censored Data
  • Censored data are data where the exact value is not known, but it is known that the value is above or below a threshold,
    • “Greater Than”
    • “Less Than”
  • or is approximate
    • “Estimated”
    • Fecal coliform bacteria only
    • Method dependant
regressions
Regressions
  • Simple linear regression (red line) is not appropriate because both variables being compared have error associated with the measurements
  • Orthogonal least squares regression(black line) is more appropriate
so what s the hold up

So what’s the hold-up?

Other Considerations

is it reasonable and realistic to protect all waters the same
Is it reasonable and realistic to protect all waters the same?
  • Enterococcus and E. coli allow for different values based on frequency of use for full body (primary) contact recreation:
    • Designated Beach
    • Moderate Full Body Contact Recreation
    • Lightly Used Full Body Contact Recreation
    • Infrequently Used Full Body Contact Recreation
which illness rate should be used when developing standards
Which illness rate should be used when developing standards?
  • All of the following illness rates are considered by EPA to be protective of primary contact recreation and support the swimmable goal of the Clean Water Act:
    •   5 illnesses per 1000 swimmers*
    • 8 illnesses per 1000 swimmers
    • 9 illnesses per 1000 swimmers
    • 10 illnesses per 1000 swimmers
slide22

Possible E. coli Criteria

Current Fecal Coliform Criteria

Different Possible E. coli CriteriaAll Support the Swimmable Goal of Clean Water Act (i.e., safe for primary contact recreation)
should seasonal differences be considered
Should seasonal differences be considered?
  • Some States include different numeric criteria for different times of year
    • More strict criteria for warmer months, for example March through October,
    • and less strict criteria for colder months when intentional full body immersion is less likely
additional discussion needed with epa
Additional discussion needed with EPA
  • Can we implement an immediate change to one new standard, i.e. drop fecal coliforms completely for freshwaters and replace with a new indicator?
  • Or would it be necessary to operate with two simultaneous indicator standards, i.e. fecal coliforms AND a new indicator?
additional discussion needed with epa25
Additional discussion needed with EPA
  • Can we convert approved fecal coliform TMDLs to a new pathogen indicator?
    • EPA has approved (Regions 10 & 3) translator methods from fecal coliforms to E. coli for TMDL purposes for some states
      • Ohio EPA Bacterial TMDL Correlation Equations for Converting Between Fecal Coliform and E. Coli
      • Oregon DEQ
      • Virginia DEQ
one facility
One Facility
  • Strong relationship between fecal coliform and E. coli; no obvious correlation for enterococci.
  • Therefore, no value in changing.
  • It would be costly and inefficient for permittees and certified laboratories to convert from fecal coliform to another bacteriological indicator at this time.
association of 21 owners and operators of publicly owned treatment works
Association of 21 Owners and Operators of Publicly Owned Treatment Works
  • Change to E. coli
  • Use a risk factor of 10 illnesses per 1000 “very aggressive threshold of protection”
  • Include seasonal variations with less restrictive criteria applicable from November through March
  • For assessing ambient attainment use monthly geo mean only
collective response of 11 environmental conservation groups
Collective Response of 11 Environmental & Conservation Groups
  • Change to E. coli
  • Use a risk factor of 5 illnesses per 1000 “to ensure that public health protected to the greatest extent possible”
  • Single standard uniform across State
  • No seasonal variation
private individual
Private Individual
  • Adopt those standards that are most protective of the public health of those engaged in primary contact recreation
  • Seasonal bacterial standards should also be considered
want more information
Want more information?
  • Evaluation of Freshwater Recreational Uses and Bacteria Main Page: http://www.scdhec.gov/environment/water/fwater.htm
  • Raw data available at: http://www.scdhec.gov/environment/water/fw_PIS.htm
  • Correlation and Regression analysis handout: http://www.scdhec.gov/environment/water/docs/fw_evaluation.doc
want more information32
Want more information?
  • EPA website on pathogens and development of water quality standards at:

http://www.epa.gov/waterscience/

criteria/humanhealth/microbial/

that s all folks

That’s All Folks!

Any Questions?

Discussion?