The coliform bacteria
in our intestines
aid in the digestion
. This particular subgroup is associated with the fecal matter
of warm-blooded animals
. The bacteria in and of themselves don't really pose a health
threat to human being
s- but don't get your swim trunks
The detection of fecal coliform bacteria in water is used mainly as a public health flag for the other nasty pathogens existing in fecal material: typhoid, hepatitis A, dysentery, cholera, and gastroenteritis, for example.
The main sources of contamination in waterways are sewer overflows, treatment plant failure, septic tank failure, plus agricultural runoff, urban runoff, and wildlife (where rain sends animal waste into the waterways).