cost-effective manner. More detailed recommendations on chemical source tracking are found in the SIPP manual [6] and Hagedorn and Weisberg [98]. Canine
scent tracking is a new and novel field approach that involves dogs trained to
respond to the scent of municipal wastewater [99]. Only a few reports of fecal
scent tracking with dogs are available, but the reports indicate reasonable success.
A major advantage of canine scent tracking is that it provides instant, on-the-ground
results. At this point, canine scent tracking appears to be a promising tool for
screening and prioritizing sampling locations before DNA-based and other similarly expensive assays are used to confirm human fecal contamination.
Step 4: Where steps 1–3 have indicated that human sources are a likely contributor, waters should be tested for the human-source-specific genetic markers
described in Sect. 3.4 (even if traditional or novel tools have not identified a leaking
sanitary or CSO system). The highest priority at this point is placed on either
detecting or confirming a human fecal source as human fecal pollution poses the
greatest relative health risk to people. Sampling for this purpose might consist of
routine sampling schemes in ambient waters or involve more intensive sampling
around precipitation or tidal events.
Step 5: Where human sources have been documented (or dismissed if conclusively proven not present) and the relative human loadings are better understood
and/or animal fecal pollution sources are likely (e.g., birds or dogs at beaches,
agricultural runoff in rural watershed areas), then waters should be tested using the
non-human (animal) source-specific markers described in Sect. 3.5. Like the human
markers, such sampling might be in ambient waters or more intensive sampling
around precipitation or tidal events.
Step 6: If fecal sources are suspected where markers have yet to be developed
(sources not included in Sect. 3.5), then testing waters with community analysis
methods as described in Sect. 4 should be considered. Another potential use of
community analysis methods may be to differentiate human fecal sources between
municipal sewage and rural septage. Community methods may be complemented
with chemical methods (as appropriate) to provide additional independent information, particularly when sewage or other human waste is a suspected source or
when multiple major sources are suspected.
6 Ongoing Research
Substantial efforts have been undertaken over the past decade to identify and
remove human sources of fecal contamination in recreational waters, especially
in urban coastal environments in California and the Great Lakes [100]. However,
numerous beaches and other recreational waters still have persistent advisories due
to high FIB counts [101]. Further improvement in water quality at such locations
requires two necessary developments [102]. First, establishing with a high degree of
certainty whether or not the remaining fecal signature is human or non-human in
origin (as described in Sects. 3, 4, and 5). Second, identifying what is needed to
280
B. Badgley and C. Hagedorn
scent tracking is a new and novel field approach that involves dogs trained to
respond to the scent of municipal wastewater [99]. Only a few reports of fecal
scent tracking with dogs are available, but the reports indicate reasonable success.
A major advantage of canine scent tracking is that it provides instant, on-the-ground
results. At this point, canine scent tracking appears to be a promising tool for
screening and prioritizing sampling locations before DNA-based and other similarly expensive assays are used to confirm human fecal contamination.
Step 4: Where steps 1–3 have indicated that human sources are a likely contributor, waters should be tested for the human-source-specific genetic markers
described in Sect. 3.4 (even if traditional or novel tools have not identified a leaking
sanitary or CSO system). The highest priority at this point is placed on either
detecting or confirming a human fecal source as human fecal pollution poses the
greatest relative health risk to people. Sampling for this purpose might consist of
routine sampling schemes in ambient waters or involve more intensive sampling
around precipitation or tidal events.
Step 5: Where human sources have been documented (or dismissed if conclusively proven not present) and the relative human loadings are better understood
and/or animal fecal pollution sources are likely (e.g., birds or dogs at beaches,
agricultural runoff in rural watershed areas), then waters should be tested using the
non-human (animal) source-specific markers described in Sect. 3.5. Like the human
markers, such sampling might be in ambient waters or more intensive sampling
around precipitation or tidal events.
Step 6: If fecal sources are suspected where markers have yet to be developed
(sources not included in Sect. 3.5), then testing waters with community analysis
methods as described in Sect. 4 should be considered. Another potential use of
community analysis methods may be to differentiate human fecal sources between
municipal sewage and rural septage. Community methods may be complemented
with chemical methods (as appropriate) to provide additional independent information, particularly when sewage or other human waste is a suspected source or
when multiple major sources are suspected.
6 Ongoing Research
Substantial efforts have been undertaken over the past decade to identify and
remove human sources of fecal contamination in recreational waters, especially
in urban coastal environments in California and the Great Lakes [100]. However,
numerous beaches and other recreational waters still have persistent advisories due
to high FIB counts [101]. Further improvement in water quality at such locations
requires two necessary developments [102]. First, establishing with a high degree of
certainty whether or not the remaining fecal signature is human or non-human in
origin (as described in Sects. 3, 4, and 5). Second, identifying what is needed to
280
B. Badgley and C. Hagedorn