|
The cleanest, best tasting water
may contain undetected contaminants. Water contaminated with harmful
bacteria, nitrates or nitrites can cause diarrhea, cramps, nausea, headache,
serious illness, even death. Accurately detect the presence of coliform
bacteria, including E. coli. in your
drinking water by using a Bacteria Test Kit.
Bacteria in Drinking Water
Can bacteria in water make me sick?
The transmission of disease through drinking water is
one of the primary concerns for a safe water supply. Human illnesses such
as typhoid, dysentery, chlorea, hepatitis, and giardiasis have been linked
to drinking water contaminated by human waste.
Can bacteria in water affect livestock?
Bacteria levels for livestock vary with intended water
use (Table 1). Adult animals are more tolerant of bacteria than young
animals. Water for cleaning and sanitizing must be of very high quality to
prevent infections and contamination of food products.
| Table 1. Bacteria guidelines for livestock water
supplies |
| Adult animals |
1000 fecal coliforms/100 ml |
| Young animals |
1 fecal coliform/100 ml |
| Dairy wash water |
1 coliform/100 ml |
How to tell if water is contaminated with bacteria.
Testing a water supply for a specific disease causing
organisms is expensive. Handling and culturing disease organisms requires
special training and equipment. Also, if the water supply is being
contaminated by human wastes, but the disease organism is not present the
day a sample is taken, the risk of future exposure to the illness is still
present.
Instead, water supplies are tested for an indicator of
human or animal waste-coliform bacteria. Coliforms do not cause disease.
They are, however, always present in the digestive systems of humans and
animals and can be found in their wastes. Coliforms are also present in
the soil and plant material.
If a water supply is found to contain coliform bacteria
it may be contaminated by sewage or manure, and there is a risk of
exposure to water-borne disease. The test for coliform bacteria is
relatively inexpensive (usually $6 to $15 per sample) and easy to perform.
To determine whether the bacteria present is from human
or animal waste, additional tests must be performed. Coliform bacteria
also could come from natural sources such as soil or decaying vegetation.
Some coliform bacteria are only present in fecal material; these are
called fecal coliforms. These bacteria indicate the presence of human or
animal waste.
A test for a third bacteria, fecal streptococci, must
be performed to determine if it is of human or animal origin. The ratio of
fecal coliforms to fecal streptococci vary for different animals (Table
2). If the ratio is near four, the waste is from humans. The ratio is less
than one for animal wastes.
Another type of bacteria, referred to as iron
bacteria, is a major nuisance in many well water supplies. (Iron
bacteria should not to be confused with iron dissolved in water that
causes red water and stains on clothing and plumbing fixtures.) This
naturallyoccurring bacteria does not cause disease, but does form a
reddishbrown slime that coats the inside of pipes, fouls pumps and clogs
waterers.
| Table 2. Typical fecal coliform/fecal streptococci
ratios for humans and various animals |
| Human |
4.4 |
| Duck |
0.6 |
| Sheep |
0.4 |
| Chicken |
0.4 |
| Pig |
0.4 |
| Cow |
0.2 |
| Turkey |
0.1 |
How to collect and handle a water sample
Proper collection and handling of a water sample is
critical for a meaningful water test. Sample containers should always be
obtained from the testing laboratory because containers may be specially
prepared for a specific contaminant. Sampling and handling procedures will
depend on the specific water quality concern and should be followed
carefully. If the water is being treated, it may be necessary to sample
both before and after the water goes through the treatment equipment.
Bacteria sampling
Water samples for bacteria tests must always be
collected in a sterile container. Take the sample from an inside faucet
with the aerator removed. Sterilize by flaming the end of the tap with a
disposable butane lighter. Run the water for five minutes to clear the
water lines and bring in fresh water. Do not touch or contaminate the
inside of the bottle or cap. Carefully open the sample container and hold
the outside of the cap. Fill the container and replace the top.
Refrigerate the sample and transport it to the testing
laboratory within six hours (in an ice chest). Many labs will not accept
bacteria samples on Friday so check the lab's schedule. Mailing bacteria
samples is not recommended because laboratory analysis results are not as
reliable.
Iron bacteria forms a very obvious slime on the inside
of pipes and fixtures. A water test is not needed for identification.
Check for a reddish-brown slime inside a toilet tank or where water stands
for several days.
What should I do if my water is contaminated with bacteria?
First, don't panic' Bacterial contamination is very
common. Studies have found that over 40 percent of private water supplies
are contaminated with coliform bacteria. Spring water supplies are the
most frequently contaminated, with over 70 percent containing coliform
bacteria.
Improving protection of a well or spring from
the inflow of surface water is an important option to consider if the
supply is contaminated with bacteria. It is important to remember that the
groundwater is not necessarily contaminated in these cases, rather the
well is acting to funnel contaminants down into the groundwater.
Although well pits were the common method of
construction several years ago, they are no longer considered sanitary
construction.
A properly protected well is evidenced by the well
casing extending above the surface of the ground and the ground sloping
away from the well to prevent water from collecting around the casing.
A properly protected spring is developed underground
and the water channeled to a sealed spring box. At no time should the
water be exposed to the ground surface.
Keeping the plumbing system clean is an
important part of maintaining a sanitary water supply. Anytime work is
performed on the plumbing or pump, the entire water system should be
disinfected with chlorine. Simply pulling the pump out of the well,
setting it on the grass to work on it, and returning it to the well is
enough to contaminate the well with bacteria.
The procedure for cleaning and sanitizing a well or
spring with chlorine is called shock chlorination. Concentrations
of chlorine ranging from 50 to 200 mg/1 are used in the shock chlorination
process. This is 100 to 400 times the amount of chlorine found in "city
water." The highly chlorinated water is held in the pipes for 12 to 24
hours before it is flushed out and the system is ready to be used again.
Periodic shock chlorination also may be effective in
reducing an iron bacteria problem. The amount of chlorine needed to
shock chlorinate a water system is determined by the amount of water
standing in the well.
Table 3 lists the amount of chlorine laundry bleach or
powdered high-test hypochlorite (HTH) that is needed for wells. If in
doubt, it is better to use more chlorine than less.
--------------------------------
Reference:
Karen M. Mancl. Water Quality
Specialist & Agricultural Engineering. Bacteria in Drinking Water.
Bulletin 795. The Ohio State University. July 5, 2004 <http://ohioline.osu.edu/b795/b795_1.html;
http://ohioline.osu.edu/b795/b795_2.html; http://ohioline.osu.edu/b795/b795_3.html>. |
