Villa Angela Beach, Cleveland, Ohio. (Donna Francy)

Chemical and Pathgogen Exposure Through Recreational Waters

Rivers, lakes, and coastal areas can become contaminated with fecal pathogens that threaten the health of people who recreate in the polluted water. Fecal contamination can be persistent over time or occur in short-lived events and has a variety of causes, such as combined sewer overflows, street water runoff during storms, wastewater treatment plant discharges, leaking pipes or septic tanks, and even fecal waste from wildlife, swimmers, or boats. Identifying and reducing the sources of fecal contamination to a particular beach is often hindered by the presence of multiple sources, natural variability in bacterial indicator concentrations over space and time, and the dynamic currents, weather patterns, and natural processes that affect these concentrations.

Currently, swim advisories or closings are issued by beach managers on the basis of standards for concentrations of fecal indicator bacteria, such as Escherichia coli or enterococci. Exposure to pathogens by swimming in fecal-contaminated waters can lead to skin, ear, eye, respiratory and intestinal problems and in rare instances life-threatening illness, however the specific pathogens associated with fecal pollution are as varied as the sources of that pollution. The most cost-effective methods for counting fecal indicator bacteria currently take 18-24 hours. During this period, indicator concentrations may change dramatically and beach managers may erroneously use the previous day’s results to evaluate current beach conditions. Beach advisories and closures intended to protect swimmers can cause loss of valuable recreation access and disrupt local tourism-dependant businesses. Beach managers need more timely methods for determining indicator bacteria numbers, better information on the complex environmental processes that govern these numbers, enhanced approaches to developing predictive capability, information on the sources of fecal contamination, and ultimately, data on the presence of pathogens themselves.

USGS assists beach managers by providing the scientific understanding to improve the design and interpretation of beach monitoring programs, by helping to understand shoreline physical and biological processes, by development of models that improve prediction of beach conditions, and by developing improved methods of measuring for occurrence of indicators and pathogens.

More information about USGS beach science capabilities.

Information about USGS activities on the following recreational water quality topics:

• Pathogen Analysis and Non-Point Sources
• Source-Tracking Methods
• Physical Processes Affecting Near Shore Contamination
• Developing Models to Forecast Beach Conditions
• Nowcasting bacteria levels and swim advisories. A web site that presents beach advisories based on a predictive model for E. coli at one Lake Erie Beach, Huntington, in Bay Village, Ohio. Models for other beaches will be added to the web site as they are validated and tested in future years.
• Measuring Policy Effectiveness and Impacts on Beach Visitors
• Microbiology and Public Beach Safety: Integrated Science for the Protection of Public Health

Other Internet Resources

• US EPA Beaches page
• Great Lakes Beach Association
• The Rouge River Demonstration Project
• Southern California Coastal Water Research Project
• Surfrider Foundation
• Heal the Bay’s Beach Report Card
• Natural Resources Defense Council Testing the Waters 2004 Report

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U.S. Department of the Interior | U.S. Geological Survey
URL: http://health.usgs.gov/rec_waters/index.html
Page Contact Information: Herb Buxton
Page Last Modified: 07-Dec-2007@10:29