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

Background Problem statement Objectives Scope Approach Benefits

PROJECT DESCRIPTION
Background

The Chattahoochee River National Recreation Area (CRNRA) was authorized by Congress in 1978 to include 48 miles of the Chattahoochee River, its bed and banks, as well as several land-based areas adjacent to the river (map). Congress declared that portions of the river were of "special national significance, and that such values should be preserved and protected from developments and uses which would substantially impair or destroy them." The Chattahoochee River is the main source of drinking water for more than 2 million people and protection of the river and water quality is the paramount intent of the enabling legislation. This fact is clearly stated in the CRNRA enabling legislation of 1978 and is reaffirmed in the 1984 amendment, which recognized a protective corridor extending 2,000 feet on either side of the river. Improving water quality and the collection of baseline water-quality data are National Park Service (NPS) goals to be attained through the Government Performance and Results Act. This project will assist the NPS in fulfilling these goals. Population in the 13-county area doubled from about 1.6 million people in 1970 to 3.1 million people in 1995; land area devoted to residential, commercial, and other urban uses more than tripled during the same period. The rapidly growing metropolitan Atlanta suburbs continue to expand into the headwaters of the Chattahoochee River and will eventually encircle the upstream reaches of the CRNRA (map). In addition to suburban and urban land use, the CRNRA watershed includes forests and poultry production areas-particularly upstream of Lake Sidney Lanier. In 1998 the Chattahoochee River was designated the seventh most endangered river in North America by American Rivers, a nationally recognized river conservation group. High levels of fecal-indicator bacteria are the principal basis for impairment of the Chattahoochee River and its tributaries in the CRNRA. Water-based recreation use constitutes 25-30 percent of 3.5 million yearly visits to the CRNRA. Microbial contamination has the potential to reduce the use and recreational value of the CRNRA and represents a continued threat, with unknown health risk to humans and pets that come in contact with the water while fishing, boating, rafting, wading, and swimming. There are numerous potential sources of microbial contaminants within the highly populated and mixed land-use setting of Metropolitan Atlanta and the upper Chattahoochee River watershed. Leaking and overflowing sanitary, raw or partially treated sewage that is bypassed at pumping stations and wastewater treatment facilities are highly publicized point sources of microbial contaminants. However, the watershed contains additional, less publicized sources of microbial contaminants from nonpoint sources including, leachate from septic systems, storm runoff of fecal material from wildlife and pets, and wastes from poultry and livestock production areas. Problem Statement High levels of fecal-indicator bacteria are the principal basis for impairment of streams in metropolitan Atlanta, including the Chattahoochee River and its tributaries. The levels of microbial contamination are of particular concern in the Chattahoochee National Recreational Area (CRNRA) where people and pets are in contact with potentially contaminated water. However, no information is available to: evaluate sources and relative quantities of microbial contaminants in the CRNRA and its major tributaries over the range of streamflow conditions and other predictor variables, evaluate relations between levels of indicator bacteria and the waterborne pathogens that pose human health risks, and provide timely dissemination of water-quality information that can be used by resource managers and recreational users of the CRNRA. Objectives Relate microbial levels to predictor variables (stream stage, streamflow, turbidity, and field water-quality parameters) and evaluate stream status over a range of hydrologic conditions in river reaches with different land use and sewered characteristics within the Chattahoochee River National Recreation Area (CRNRA). Evaluate sources of microbial contaminants relative to tributary stream baseflow and stormflow periods and peak recreational use periods. Evaluate occurrence and distribution of pathogens and viruses relative to fecal-indicator bacteria. Relate occurrence and distribution of microbial contaminants to presence and source of domestic wastewater based on concentrations of chemical sewage tracers. Evaluate changes in microbial levels as a result of varying releases from Lake Sidney Lanier and diel fluctuations in sunlight and temperature. Provide timely dissemination of fecal-indicator bacteria data that can be used by resource managers and recreational users of the CRNRA to better evaluate the safety of water contact recreational activities. Scope 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 will be six months of microbial sampling in each fiscal year spanning from April 1, 1999 through March 30, 2000. This study will measure 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. Approach The 2-year project will investigate 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: 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) 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. 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: Chattahoochee River at Settles Bridge Road near Suwanee Chattahoochee River at Johnsons Ferry Road near Atlanta Chattahoochee River at Atlanta (Paces Ferry Road; downstream from Palisades Unit) 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: James Creek near Cumming (James Burgess Road) Suwanee Creek near Suwanee (at US Route 23, Buford Hwy) Johns Creek near Warsaw (Buice Road) Crooked Creek near Norcross (Spalding Road) Big Creek near Roswell (below Water Works intake) Willeo Creek near Roswell (State Route 120) Sope Creek near Marietta (Lower Roswell Road) 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. Bibliographic references: Cabelli, V.J., 1977, Indicators of recreational water quality, in Hoadley, A.W., and Dutka, B.J., eds., Bacterial indicators/health hazards associated with water, 1977: American Society for Testing and Materials, ASTM STP 635, p. 222-238. International Association on Water Pollution Research and Control, Study group on health related water microbiology, 1991, Bacteriophages as model viruses in water quality control: Water Research, v. 25, no. 5, p. 529-545. Myers, D.N., and Sylvester, M.A., 1997, National field manual for the collection of water-quality data-Chapter A7. Biological Indicators: U.S. Geological Survey Techniques of Water-Resources Investigations: ed Myers, D.N., and Wilde, F.D., variously paginated. Sorensen, D.L., Ebertl, S.G., and Dicksa, R.A., 1989, Clostridium perfringens as a point source indicator in nonpoint polluted streams: Water Research, v. 23, no. 2, p. 191-197. Benefits Improving water quality and the collection of baseline water quality data are National Park Service (NPS) goals to be attained through the Government Performance and Results Act. This project is assisting the Chattahoochee River National Recreation Area (CRNRA) with fulfilling these goals by clarifying the extent, severity and frequency of microbial contamination in the Chattahoochee River and its tributaries with respect to hydrologic conditions, land use, and predictor variables. Historical data are primarily limited to fecal coliform levels measured once per month during flow conditions that aretypical during mid-week daytime hours. Sampling design includes frequent temporal and spatial sampling. Fecal-indicator bacteria levels regularly exceed standards. However, this project will improve the understanding of the sources and relative quantities of microbial contaminants in the Chattahoochee River and its major tributaries over the range of streamflow conditions. To date, no survey has been conducted to collect baseline data to provide up-to-date values for fecal-indicator bacteria (fecal coliform, E. coli, and enterococci) entering the waterways of the park. Sampling of fecal-indicator bacteria and coliphages will provide a better understanding of potential public-health risks. It will also help determine the correlation between indicator-bacteria levels and waterborne pathogens that pose human-health risks within the CRNRA. Sampling of chemical sewage tracers during a wide range of hydrologic conditions will enable better definitions of point and nonpoint sources of microbial contamination. Microbial contamination is a potential problem in all urban areas and for all parks with aquatic recreation. Results from this study will be helpful to State and local agencies in developing regional management plans to reduce microbial contamination in the Chattahoochee watershed. Regulatory and management agencies will benefit by being able to compare results from their fecal coliform measurements with the more widely recommended E. coli and enterococci indicator bacteria. All data collected and analyzed by this project will be available on the World Wide Web.

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Last Modified: Tuesday, 19-Oct-1999 08:32:52 EDT