Science and Resource Considerations for Microbial Source Tracking

1
Science and Resource Considerations for
Microbial Source Tracking

• Steve Jones
• Jackson Estuarine Laboratory
• University of New Hampshire
• Durham, NH
• May 5, 2006
• FRESHWATER BEACH CLOSURES, FAIRLEE, VT

2
THE ISSUE
Water quality at bathing beaches is a concern
because of the potential for disease transmission
through contact with microbial pathogens. To
manage this problem, sources of the pathogens
need to be identified and eliminated.
Traditional source identification approaches and
subsequent management actions often do not result
in significant improvements in water quality.
Microbial Source Tracking (MST) methods have
recently been developed that allow for
identification of the pollution sources that are
the most significant sources or threats to public
health. This new approach serves to focus
management efforts and save valuable resources.
3
WHEN, WHY HOW Should MST be Used?

• What is the problem and the desired outcome?
• What level of accuracy is required?
• When are results needed?
• What is already known about the beach?
• What are the conditions of concern?
• Precede or follow a sanitary survey.
• ARE THERE MULTIPLE OR UNKNOWN SOURCES? YES?
  MST!!

4
MST Study Approach

• Consider area of study
• Drives resource needs expected results
• Smaller area gtgt success
• Tiered approach
• Use low-cost measurements 1st
• Identify probable sources
• Iteratively smaller area, number of probable
  sources more defined conditions of concern
• Multiple MST and other methods

5
MSTDiscrimination Level

• Human vs. non-human?
• Non-human species discrimination?
• Types of non-human sources?
• Individual animals or sources?
• --gt Dictates type of MST method required (library
  dependence)

6
The best results that can be accomplished with
MST is an estimate of the relative contributions
of different sources in the study area at the
time and conditions of sampling.
7
General Characteristics of MST Methods
8
Factors Defining Advantages and Disadvantages
in Comparing MST Methods
9
So, Which MST Method Should Be Used?

• The results of several comparative studies that
  included many different MST methods suggest that
  all tested methods provided useful information,
  and often differed in capabilities depending on
  what type of information was desired no method
  clearly superior!
• Library-dependent methods known limitations
  Library independent-less available information
• The best approach is to use experienced entities
  who encourage a tiered approach, have
  local/regional knowledge and can employ multiple
  MST methods.
• Beware of promises of the SILVER BULLET!

10
Non-MST Methodsfor Fecal Contamination

• Optical Brighteners UV or fluorometric detection
• Fecal-borne chemicals
• -sterols
• -immunoglobins
• -human nucleic acids
• Wastewater-derived chemicals
• -Propranolol, Ibuprofen, Caffeine
• -Different biodegradation rates for chimers
  allow for discrimination of degree of treatment
  of wastewater

11
Combined Use of Fecal-Borne Bacteria and Optical
Brightener Detection for MST
12
Follow-up to MST Study

• Information on pollution sources
• Are identified sources likely?
• Management strategy
• Human vs. non-human sources risk
• Potential for elimination of source
• EXAMPLE MST STUDY RESULTS

13
Source Species Types Identified During Wet Dry
Weather at Atlantic Coast Beaches, NH
14
Regional-Escherichia coli (EcoR1)Source Species
Database
31 total species/sources 5 TYPES
15
MST Study Sites at NH Atlantic Coast Beaches
16
Source Species Types at NH Atlantic Coast Beaches
During Wet Weather 2003
17
(No Transcript)
18
(No Transcript)