Pointing a finger at the source of fecal bacteria

May 23, 2007
Plum Creek Watershed
Plum Creek watershed, south-central Nebraska Credit: Jason R. Vogel, USGS

Excessive levels of fecal bacteria were to blame for almost 60 percent of Nebraska streams deemed impaired by federal and state environmental laws in 2004. In order to develop effective pollution-control strategies, it is important for researchers to identify the source of the contamination. By using multiple methods, or a “toolbox” approach, to determine the origin of fecal pollution in streams, researchers were able to identify the source of fecal bacteria with greater certainty than if testing with a single method.

In collaboration with the Nebraska Department of Environmental Quality, the U.S. Environmental Protection Agency (EPA), and the University of Cincinnati, U.S. Geological Survey (USGS) scientists used a toolbox approach when investigating the sources of fecal bacteria within the Plum Creek watershed in south-central Nebraska. The scientists report their findings in the May-June 2007 issue of the Journal of Environmental Quality.

This research was funded by the Nebraska Department of Environmental Quality, the U.S. Geological Survey Cooperative Water Program, and the U.S. Environmental Protection Agency.

In 2001, monitoring studies by the Nebraska Department of Environmental Quality named Plum Creek the most contaminated tributary to the middle reaches of the Platte River. The researchers used two fecal source-tracking tools to analyze contaminated water and stream-sediment samples in the Plum Creek watershed.

The source-tracking tools use genetic material from bacteria collected in water and sediment samples to determine their source, either by comparing the genetic material with that of known fecal bacteria sources, or by looking for a “marker” within the genetic material that is associated with a specific fecal source. The results of the study revealed that cattle and wildlife were the dominant sources of fecal bacteria found in water and stream sediment samples at the main study site located in an upper reach of the creek.

“While the two methods led to similar overall interpretations, using both methods together gave us a clearer picture of potential sources and the strengths and weaknesses of the methods used,” said USGS Hydrologist Jason Vogel, lead author of the study. “Additionally, results from bacteria found in stream-bottom sediment also suggest that different tools for tracking fecal contamination may have varying relevance to the more specific goal of tracking the sources of E. coli in water or soil within the watershed.”

Ongoing studies at the USGS and EPA are testing the use of microorganisms as tools for tracking fecal contamination. Fecal bacteria can enter watersheds from specific sources such as wastewater treatment outfalls, and diffuse sources such as runoff from fields where livestock waste has been applied as fertilizer. Determining the source of the bacteria is necessary to implement appropriate pollution-control practices and comply with water-quality standards required by the Clean Water Act. Further research is needed to continue to develop and refine existing and new tools for identifying the sources of fecal contamination in water and sediment.

Source: American Society of Agronomy

Explore further: Unsafe levels of toxic pollutants in heavily fracked Ohio county

Related Stories

Architects to hatch Ecocapsule as low-energy house

18 hours ago

Where people call home depends on varied factors, from poverty level to personal philosophy to vanity to community pressure. Ecocapsule appears to be the result of special factors, a team of architects applying ...

California farmers agree to drastically cut water use

22 hours ago

California farmers who hold some of the state's strongest water rights avoided the threat of deep mandatory cuts when the state accepted their proposal to voluntarily reduce consumption by 25 percent amid ...

Apple may deliver ways to rev up the iPad, report says

22 hours ago

MacRumors last month said that the latest numbers from market research firm IDC's Worldwide Quarterly Tablet Tracker revealed Apple stayed on as the largest vendor in a declining tablet market. The iPad ...

Recommended for you

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.