Total coliform testing is very useful when monitoring
drinking water, as the presence of any of these bacteria would
suggest a problem with water treatment. Use of total coliform
monitoring for swimming areas has mixed value. On one hand, high
total coliform numbers would suggest a potential problem even
if the more harmful bacteria were not present at the actual time
of sampling. The down side to using total coliform is that you
may find that the bacteria are always present, and concern over
water contact might be overrated.
Fecal Coliform
This is a sub-group of bacteria under the total coliform grouping.
These bacteria are found in the guts of warm blooded animals (humans,
livestock, pets, waterfowl, etc). Presence of these bacteria indicate
a fecal contamination of the water. These bacteria can cause diarrhea,
stomach cramps, and nausea. Non-fecal bacteria are not measured
with this test.
Monitoring fecal coliform bacteria gives you an exact number
of potentially harmful bacteria in the water (as opposed to an
indicator of possible presence). The drawback to monitoring just
fecal coliform is that these bacteria are relatively short-lived
in the environment. A low reading may not give you a good indication
of what was present the day before.
In Missouri, the acceptable level for fecal coliform is less
than 200 cells (colony forming units) per 100 mL of water. If
a reading is equal to or higher than this, the water is deemed
unsafe for full body contact.
E.coli
Escherichia coli is a specific bacteria that falls under the fecal
coliform heading. There are many strains of this one type of bacteria
and most are harmless. There is one strain, E. coli 0157:H7, that
produces a powerful toxin and can lead to serious illness.
Dan Obrecht
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