Steve Tuckerman, Ohio EPA
Figure 1. An attraction to kayakers, canoeists, and swimmers, the Cuyahoga River can be unsafe because of discharges from stormwater, sewer overflows, and urban wastewater. Managers at Cuyahoga Valley National Park have been testing a method to provide same-day information on E. coli levels in the Cuyahoga River that would improve their ability to protect the health of water enthusiasts.
Conventional methods for determining recreational water quality are based on concentrations of fecal-indicator bacteria, such as Escherichia coli. When found in water, E. coli indicates contamination from human and animal waste and the possible presence of disease-causing organisms. Determining levels of fecal-indicator bacteria by conventional methods requires at least 18 hours to process and culture samples before results are available. This length of time is too long to assess water quality, take adequate control measures, and warn recreational users of a health hazard. Decay, dilution, dispersion, and transport of fecal-indicator bacteria in water cause concentrations to change greatly over short periods of time. Because results from conventional methods are not available until the following day, the safety of the water for recreational use may not be accurately assessed. The need for a rapid method that provides reliable results of the current day’s bacteria concentrations is widely recognized.
When found in water, E. coli indicates contamination from human and animal waste and the possible presence of disease-causing organisms.
U.S. Geological Survey (USGS) scientists, in partnership with the National Park Service (NPS), have been testing a rapid method in Cuyahoga Valley National Park, Ohio, that provides estimates of E. coli concentrations in approximately one hour. This rapid method was developed by Lee and Deininger (2004). Previous studies at the University of Michigan showed a strong, significant correlation between the rapid and conventional methods for E. coli in samples collected from two Great Lakes beaches, two inland beaches, and the Huron River (Lee and Deininger 2004). The purpose of this study is to compare the results of the rapid method to results of the conventional method for determining concentrations of E. coli. Water samples were collected during the May-through-September recreational seasons of 2004 and 2005 at three sites on the Cuyahoga River within Cuyahoga Valley National Park.
The Cuyahoga River connects the national park with the largest system of freshwater in the world: the Great Lakes. The fabled river that burned brought international attention to water-quality issues and encouraged cleanup through the passage of environmental legislation, especially the Clean Water Act. Over the past few decades, the water quality of the Cuyahoga River has improved considerably and the river was designated by the Environmental Protection Agency in 1998 as one of 14 American Heritage Rivers; however, the water quality of the Cuyahoga River is still a primary concern of park managers and visitors. The 23-mile reach of the river within the park receives discharges of stormwater, combined-sewer overflows, and incompletely disinfected wastewater from urban areas. Park visitors are discouraged from canoeing, swimming, and wading in the river because these discharges can be a threat to their health (fig. 1, top of page).
Until improvements in the treatment, disinfection, and detention of sewage and storm-water overflows upstream of the park’s boundary become a reality, resource managers need an interim approach to protect human health and to provide safe, water-based recreation for park visitors. Without a realistic method to determine daily water-quality conditions, use of the river will be discouraged, even when fecal indicator concentrations are at safe levels.
Without a realistic method to determine daily water-quality conditions, use of the river will be discouraged, even when fecal indicator concentrations are at safe levels.
