Microbial Contamination of Water Resources in the Chatahoochee River National Recreation Area, Georgia

The study area is the watershed for the Chattahoochee River from Buford Dam to
just downstream of the mouth of Peachtree Creek. This study area includes the
entire Chattahoochee River National Recreation Area, much of Metropolitan
Atlanta, and extends downstream of two major wastewater treatment plant
outfalls for the City of Atlanta and Cobb County.

The 2-year study is for fiscal years 1999 and 2000. There are six months of
microbial sampling in each fiscal year spanning from April 1, 1999 through
March 30, 2000.

This study measures fecal-indicator bacteria (fecal coliform, E. coli, and
enterococci) every five days from April 1, 1999 to September 30, 1999 and every
8 days from October 1, 1999 to March 30, 2000 at three main stem Chattahoochee
River sites. The five-day and eight-day sampling intervals will ensure mid week
and weekend flow conditions are sampled. Indicator bacteria samples will also
be collected during one 26-hour period to look at diel fluctuations. Another
indicator bacteria (Clostridium perfringens), F-specific coliphages, somatic
coliphages, and chemical sewage tracers will be measured as part of several
synoptic surveys at 3 fixed sites and 9 synoptic sites.

The 2-year project investigates the existence, severity, and extent of
microbial contamination in the Chattahoochee River and 8 major tributaries
within the Chattahoochee River National Recreation Area (CRNRA). High levels of
fecal-indicator bacteria are the principal basis for impairment of streams in
the CRNRA. Three data-collection activities include:

1.Fixed interval: Sample fecal-indicator bacteria and predictor variables
(stream stage, stream flow, turbidity, and field water-quality parameters)
every 5 days from April 1 to September 30, 1999 and every 8 days from October
1, 1999 to March 30, 2000 at 3 Chattahoochee River sites. (view map) 2.Synoptic
surveys: Sample fecal-indicator bacteria, Clostridium perfringens, viruses,
predictor variables, and chemical sewage tracers at 4 Chattahoochee River sites
and 8 tributary sites during critical seasons and hydrologic conditions. 3.Diel
samples: Sample fecal-indicator bacteria and predictor variables every 2 hours
for one 26-hour period (August 4-5, 1999) at the Chattahoochee River at
Atlanta, which is downstream of the CRNRA.

Four proposed main stem sampling sites in downstream order on the Chattahoochee
River include:

1.Chattahoochee River at Settles Bridge Road near Suwanee
2.Chattahoochee River at Johnsons Ferry Road near Atlanta
3.Chattahoochee River at Atlanta (Paces Ferry Road; downstream from Palisades
Unit)
4.Chattahoochee River at State Highway 280, near Atlanta (Synoptic site only;
downstream from all of the CRNRA, much of Metropolitan Atlanta, and 2 major
wastewater treatment outfalls for the City of Atlanta and Cobb County; will
provide microbial data for a Chattahoochee River site directly affected by
point sources of wastewater effluent)

Eight proposed tributary sampling sites within the CRNRA watershed in
downstream order include:

1.James Creek near Cumming (James Burgess Road)
2.Suwanee Creek near Suwanee (at US Route 23, Buford Hwy)
3.Johns Creek near Warsaw (Buice Road)
4.Crooked Creek near Norcross (Spalding Road)
5.Big Creek near Roswell (below Water Works intake)
6.Willeo Creek near Roswell (State Route 120)
7.Sope Creek near Marietta (Lower Roswell Road)
8.Rottenwood Creek near Smyrna (Interstate Parkway North)

In general, fecal-indicator bacteria are used to assess the public-health
acceptability of water. The concentration of indicator bacteria is a measure of
water safety for body-contact recreation or for consumption (Myers and
Sylvester, 1997). Indicator bacteria do not typically cause diseases
(pathogenic), but they indicate the possible presence of pathogenic organisms.
Escherichia coli (E. coli) and enterococci are currently the preferred fecal
indicators for recreational freshwaters because they are superior to fecal
coliforms and fecal streptococci as predictors of swimming-associated
gastroenteritis (Cabelli, 1977; Dufour, 1984); however fecal coliforms are
still used by many states including Georgia to monitor recreational waters.
Most historical indicator bacteria data for surface water within the CRNRA are
fecal coliform counts collected once a month on a mid-weekday during normal
working hours. This study proposes to measure fecal coliform using the membrane
filter technique (preferred over the broth technique used by Georgia EPD),E.
coli, and enterococci every five days during the recreation season at three
main stem sites. The five-day cycle will ensure mid week and weekend flow
conditions are sampled. All samples will be collected using USGS protocols for
bacteria and equal width interval (EWI) sampling.

Clostridium perfringens (C. perfringens) is another indicator bacteria that is
present in large numbers in human and animal wastes, and its spores are more
resistant to disinfection and environmental stresses than are most other
bacteria. It is also a sensitive indicator of microorganisms that enter streams
from point sources (Sorenson and others, 1989). It must be analyzed under
anaerobic conditions in a laboratory and is best attempted by a biologist or
highly trained technician. This study proposes to measure C. perfringens at 4
main stem and 8 tributary sites as part of synoptic surveys during critical
seasons and hydrologic conditions.

Because monitoring of enteric viruses is recognized as being difficult,time
consuming, and expensive, some researchers advocate the use of coliphage for
routine viral monitoring. Coliphages are bacteriophages that infect and
replicate in coliform bacteria. Although somatic and Fecal-Specific coliphages
are not consistently found in feces, they are found in high numbers in sewage
and are thought to be reliable indicators of the sewage contamination of waters
(International Association on Water Pollution Research and Control, 1991).
Coliphage is also recognized to be representative of the survival transport of
viruses in the environment. However, to date, they have not been found to
correlate with the presence of pathogenic viruses. This study proposes to
measure enteric viruses at 4 main stem and 8 tributary sites as part of
synoptic surveys during critical seasons and hydrologic conditions.