E. coli can survive in streambed sediments for months

Jul 01, 2011

Studies by U.S. Department of Agriculture (USDA) scientists have confirmed that the presence of Escherichia coli pathogens in surface waters could result from the pathogen's ability to survive for months in underwater sediments. Most E. coli strains don't cause illness, but they are indicator organisms used by water quality managers to estimate fecal contamination.

These findings, which can help pinpoint potential sources of water contamination, support the USDA priorities of promoting and food safety.

Soil scientist Yakov Pachepsky works at the Agricultural Research Service (ARS) Environmental Microbial and Food Safety Laboratory in Beltsville, Md. He is conducting studies to learn more about where the E. coli pathogens in streambeds come from, where they end up, and how long they can survive. ARS is USDA's chief intramural scientific research agency.

Lab studies conducted by Pachepsky and his colleagues suggested that non-pathogenic strains of E. coli can survive much longer in underwater sediments than in the water column itself, and provided the first published evidence that E. coli can overwinter in the sediment.

The results also indicated that the pathogens lived longer when levels of organic carbon and fine sediment particles in the sediment were higher. In addition, when organic carbon levels were higher, were less likely to affect the pathogens' .

The researchers also collected three years of data on stream flow, weather, and E. coli levels in water and sediments from a stream in Pennsylvania that was fed by several smaller tributaries. Then they used the information to calibrate the Soil and Water Assessment Tool (SWAT), a model developed by ARS scientists that predicts how affect water quality on watershed scale.

The resulting simulations indicated pasture runoff contributed to E. coli levels in nearby streams only during temporary interludes of high-water flows. Since the SWAT model currently does not include data on E. coli levels in streambed sediments, this research indicates that SWAT simulations would overestimate how much E. coli contamination in surface waters is due to pasture runoff.

Results from this work were published in Research, Ecological Modeling, Critical Reviews in Environmental Science and Technology, and Journal of Hydrology.

Explore further: A mathematical theory proposed by Alan Turing in 1952 can explain the formation of fingers

Provided by United States Department of Agriculture

5 /5 (1 vote)
add to favorites email to friend print save as pdf

Related Stories

E. coli an unlikely contaminant of plant vascular systems

Apr 01, 2011

A technique developed by U.S. Department of Agriculture (USDA) scientists for tracking pathogens has helped confirm that Escherichia coli is not likely to contaminate the internal vascular structure of field-grown leafy ...

Detecting pathogens in waterways: An improved approach

Feb 08, 2011

U.S. Department of Agriculture (USDA) scientists have come up with a way to detect pathogenic Escherichia coli and Salmonella bacteria in waterways at lower levels than any previous method. Similar methods have been developed ...

'Super socks' help stem pollution runoff

Jul 23, 2010

Agricultural Research Service (ARS) scientists and their collaborators have improved on an existing method for removing contaminants from storm water runoff. These findings could provide surface waters additional protection ...

How good are tests for E. coli in streams?

Sep 22, 2009

Bacteria commonly used to indicate health risks in recreational waters might not be so reliable after all. Pathogenic E. coli were pervasive in stream-water samples with low concentrations of fecal indicator bacteria.

Recommended for you

The 'memory' of starvation is in your genes

21 minutes ago

During the winter of 1944, the Nazis blocked food supplies to the western Netherlands, creating a period of widespread famine and devastation. The impact of starvation on expectant mothers produced one of the first known ...

Sugar mimics guide stem cells toward neural fate

Jul 30, 2014

Embryonic stem cells can develop into a multitude of cells types. Researchers would like to understand how to channel that development into the specific types of mature cells that make up the organs and other structures of ...

Researchers uncover secrets of internal cell fine-tuning

Jul 29, 2014

New research from scientists at the University of Kent has shown for the first time how the structures inside cells are regulated – a breakthrough that could have a major impact on cancer therapy development.

User comments : 0