HISTORICAL TRENDS AND CONCENTRATIONS OF
FECAL COLIFORM BACTERIA IN THE BRANDYWINE BASIN,
CHESTER COUNTY, PENNSYLVANIA

This project was done in cooperation with the Chester County Water Resources Authority and the Chester County Health Department.

FINAL REPORT
Historical Trends and Concentrations of Fecal Coliform Bacteria in the Brandywine Creek Basin, Chester County, Pennsylvania [PDF File]

NEED FOR THE PROJECT

Concentrations of fecal coliform bacteria in water samples collected from the Brandywine Creek from March to October at the three U.S. Geological Survey stream-water quality monitoring stations are consistently above 200 organisms per 100 milliliters, which is the bathing-water criteria established by the U.S. Environmental Protection Agency. The Brandywine Creek flows through the heart of Chester County and is widely used for recreation and drinking water. The aesthetic, recreational, and ecological health of the creek are degraded because of the high concentration of fecal coliform bacteria. Bacteria concentrations in stormflow are typically greater than in baseflow and during storm events can reach 50,000 organisms per 100 milliliters and higher.

PROJECT OBJECTIVES

• Evaluate trends in fecal bacteria concentration data collected since 1972
• Determine the fecal bacteria concentration in the Brandywine Creek and its major tributaries
• Identify potential subbasin sources for fecal bacteria contamination
• Determine bacteria concentrations at different flow regimes and seasons and identify the hydrologic conditions associated with elevated concentrations of bacteria
• Determine the relation between land use and fecal bacteria concentration
• Determine the concentration of Escherichia Coli (E. coli) bacteria, which are an indicator of intestinal pathogens that cause human diseases

DESIGN OF SAMPLING NETWORK

Fecal coliform bacteria were used as the primary indicator of bacterial contamination in this study because they were used in data collection from 1972-97, they are present in water when bacterial pathogens from fecal contamination are present, and they are present in higher concentrations than pathogens and so are easily detected. Fecal coliform bacteria are easy to culture and are typically harmless to humans. Escherichia coli (E. coli) bacteria were used as a secondary indicator of bacterial contamination. E. coli are found in smaller concentrations than fecal coliform bacteria and are more difficult to culture, but are a better indicator of the presence of intestinal pathogens that cause human diseases. E. coli samples were collected along with fecal coliform samples at selected sites.


SAMPLING NETWORK

A network of 40 sites was established in the Brandywine Basin for bacteria sampling. These stations were sampled at baseflow (low flow) in 1998 and both baseflow and storm flow in 1999. All stations were sampled for fecal coliform bacteria, and selected stations were sampled for E. coli bacteria.

Return to the USGS Chester County Water Resources Page

Return to the Water Resources of Pennsylvania Home Page
or go directly to:





The URL for this page is http://pa.water.usgs.gov/malvern/chesco_brandywine_bacteria.html

Please note our privacy statement and disclaimer
Accessibility