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What are Fecal Coliform Bacteria?

Fecal coliform bacteria, the most common member being Eschericia coli., are bacteria that aid in the digestion of food. This group of bacteria is passed through the fecal excrement of humans, livestock and wildlife and can enter rivers directly or from agricultural and storm runoff.

Fecal coliform are not dangerous or pathogenic; alone, they will not cause diseases and illnesses. However, they naturally occur in the human digestive tract where pathogenic organisms are often found along with fecal coliform bacteria in infected organisms. If waters are infected by fecal coliform bacteria and accompanying pathogens, they may make people sick by transmitting disease-causing organisms through cuts in the skin or even simply by ingestion.

Diseases and illness such as typhoid fever, hepatitis, gastroenteritis, dysentery, and ear infections could be contracted in waters with high fecal coliform count.

The presence of fecal coliform tends to affect humans more than it does aquatic creatures, though more research needs to be done on effects of transmission of pathogens on the environment. The presence of fecal contamination is an indicator that a potential health risk exists for individuals exposed to this water.

Lindsey Hulit '06, Microbiology Group

Microbiology: Levels of Fecal Coliform: May 4, 2005

Photograph of fecal coliform courtesy Environmental Protection Agency. Available Online: <>

Turtle Mound site

Castle site

Off-dirt road site

St. Olaf Site

Meet Cannon Site

400 MPN

MPN: (Most probable number of coliform per 100ml of H20)

> 2,400 MPN

23 MPN (inconclusive results)

(5/11 Redo of site yielded: > 2,400 MPN)

> 2,400 MPN

> 2,400 MPN

 The experiment was repeated on May 11, 2005, with the following results reported:

All sites positive, suggesting that all samples had > 200 coliform calories / 100mL of H20. These findings support our first results.

The water at Site 1 (Turtle Mound) contains the least fecal coliform bacteria of our five sites.