AU Researchers to Pinpoint Sources of Creek Contamination

AUBURN, Ala. — A team of Auburn University researchers is tracking down the sources of E. coli bacteria in three polluted Alabama creeks and, in the process, collecting data that should help improve water quality in impaired rivers and streams statewide.

In a two-year study funded by the Alabama Agricultural Experiment Station and the Auburn University Environmental Institute, the scientists — environmental soil microbiologist Yucheng Feng and soil chemist Wes Wood, both from AU’s Department of Agronomy and Soils, and wildlife biologist Steve Ditchkoff from the School of Forestry and Wildlife Sciences — will determine whether E. coli bacteria that have made stretches of Scarham Creek in DeKalb and Marshall counties, Catoma Creek in Montgomery County and Mobile County’s Juniper Creek unfit for recreational purposes are of livestock, human or wildlife origin.

Current testing mechanisms reveal only whether a waterway is contaminated with fecal bacteria; they don’t indicate whether the pollution is originating from surface runoff from livestock operations, inadequate septic or sewer systems, improper waste disposal or some other source.

“To develop effective pollution control strategies, it is not enough to know simply that fecal indicator bacteria such as E. coli are present in a stream,” Feng said. “You must know what the sources of the contamination are so that you can target those specifically.”

The researchers’ first step in the project is to create “libraries” — not ones with books and periodicals, but reference libraries that genetically catalog E. coli strains found in the feces of hundreds of different warm-blooded creatures, humans included, that live in the watersheds of the three contaminated creeks. Accomplishing that involves the unenviable task of collecting 400 fecal samples from each of the watersheds.

Analysis of the samples will lead to the establishment of host origin libraries for the three watersheds. Then the researchers will collect water samples from each creek and match the E. coli bacteria in those samples against the E. coli isolates in the host origin libraries to determine the specific sources of the contamination in the creeks and what proportions of the bacteria are from which sources.

“Knowing the proportional contribution of each source will help state regulatory authorities and local stakeholders prioritize the implementation of remedial actions,” Feng said.

In another component of the research project, the scientists will compare the host origin libraries for the three watersheds. If there is no geographic variability, that will signal that a single host origin library could be used to determine the sources of E. coli isolates in any body of water in Alabama, Feng said. That information will enable water resource managers across Alabama to identify the sources and design effective remediation and cleanup plans for contaminated streams.

The creeks targeted in this study are just three of 181 stream/river segments that fail to meet water quality standards set by the federal Clean Water Act. Juniper and Scarham creeks are ranked as high priorities on Alabama’s list, while the 23-mile stretch of Catoma Creek that is listed is considered a medium priority.

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Auburn, AL 36849
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Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu

10/08/04

For immediate release