Coliform Bacteria
The quality of marine and other recreation waters is usually determined through
testing for the presence of indicator bacteria. The indicator bacteria that are
most commonly examined are called "Coliforms". Coliform bacteria originate
from soils, plants and human and animal wastes. Although not all coliforms are harmful
to humans the presence of high numbers of coliforms in a water body is a good indicator
that the water is polluted with harmful microorganisms and viruses.
Used together coliform and fecal coliform bacteria levels are an important tool
that help scientists determine whether it is safe to surf and swim at the beach.
Surfrider's Blue Water Task Force also performs beach water tests for coliform
and fecal coliform to determine if it safe to surf or swim.
Fecal Coliform Bacteria
Fecal Coliform is a specific kind of coliform bacteria that are found primarily
in the intestinal tracts of mammals and birds. These bacteria are released into
the environment through human and animal feces. The presence of fecal pollution
may come from storm water runoff, pets and wildlife, and human sewage. If they
are present in high concentrations in recreational waters and are ingested while
swimming or enter the skin through a cut or sore, they may cause human disease,
infections or rashes.
One species of fecal coliform bacteria is the infamous E.coli bacteria, which
has been linked to numerous food born illness outbreaks in the United States.
A number of other bacteria in combination comprise the Fecal Coliform group. In
other words E. coli is not a direct substitute for Fecal Coliform. E. coli can
compromise anywhere from 5% to 90% of the Fecal Coliform in the water and usually
ranges from 80 - 90% of the Fecal Coliform. This means that when we get an E.
coli MPN number, that number is usually 80 -90% of the Fecal Coliform MPN number.
Knowing this we can perform a conversion to approximate a Fecal Coliform number
to compare to a state standard. See the Blue Water Task Force Manual for E-Coli
conversion table.
Used together coliform and fecal coliform bacteria levels are an important tool
that help scientists determine whether it is safe to surf and swim at the beach.
Surfrider's Blue Water Task Force also performs beach water tests for coliform
and fecal coliform to determine if it safe to surf or swim.
Enterococcus
The enterococcus group is a subgroup of the fecal streptococci. The enterococci
portion of the streptococcus group is a valuable bacterial indicator for determining
the extent of fecal contamination of recreational surface waters. Studies in marine
and fresh water studies indicate that enterococci are the most efficient bacterial
indicator of water quality. Enterococcus is a bacteria found in the human intestine
and therefore a good indicator of human waste.
According to studies conducted by the EPA, enterococci have a greater correlation
with swimming-associated gastrointestinal illness in both marine and fresh waters
than other bacterial indicator organisms, and are less likely to "die off"
in saltwater. If an enterococci result were observed to exceed 104 colony forming
units per 100 milliliters of beach water sampled and a resampling result also
exceeds this value, then an "Advisory" would be issued for the sampling
site.
coliform bacteria tester