What dangers can there be in drinking water?
A: There are several problems that can endanger the
quality of drinking water. A number of these problems
are summed up here. One can detect Coliform bacteria
in drinking water. Coliform bacteria are a group of
microorganisms that are normally found in the intestinal
tract of humans and other warm-blooded animals, and
in surface water. When these organisms are detected
in drinking water this suggests contamination from
a subsurface source such as barnyard run-off. The
presence of these bacteria indicates that disease-causing
microorganisms, known as pathogens, may enter the
drinking water supply in the same way if one does
not take preventive action. Drinking water should
be free from Coliform. Yeasts and viruses can also
endanger the quality of drinking water. They are microbial
contaminants that are usually found in surface water.
Examples are Giardia and Cryptosporidium. Giardia
is a single cell organism that causes gastrointestinal
symptoms. Cryptosporidium is a parasite that is considered
to be one of the most significant causes of diarrhoeal
disease in humans. In individuals with a normal immune
system the disease lasts for many days causing diarrhea,
vomiting, stomach cramps and fever. People with weakened
immune systems can suffer from far worse symptoms,
caused by cryptosporidium, such as cholera-like illnesses.
in drinking water can cause cyanosis, a reduction
of the oxygen carrying capacity of the blood. This
is particularly dangerous to infants under six months
of age. Lead can enter the water supply as it leaches
from copper pipelines. As the water streams through
the pipes, small amounts of lead will dissolve in
the water, so that it becomes contaminated. Lead is
a toxic substance that can be quickly absorbed in
the human systems, particularly those of small children.
It causes lead poisoning. Legionella is a bacterium
that grows rapidly when water is maintained at a temperature
between 30 and 40 degrees for a longer period of time.
This bacterium can be inhaled when water evaporates
as it enters the human body with aerosols. The bacteria
can cause a sort of flue, known as Pontiac fever,
but it can also cause the more serious deathly illness
known as legionellosis.
What is the major source of water pollution?
A: The major source of water pollution is rain. The
same rain that helps fill reservoirs, swells rivers,
and makes plants, trees and crops grow washes over
cattle feed lots in the Midwest, over dirty city streets,
over piles of industrial waste, etc. Eventually the
fallen rain, now called `runoff' goes directly into
surface drinking water sources or seeps down through
the ground into underground water sources called 'aquifers',
carrying germs or chemicals, or both with it.
How do chemicals get into my water?
A: Many of them, such as calcium, magnesium, iron,
and others, occur naturally in water, and most of
these "natural" chemicals are not harmful
to your health. However, rain seeping through a hazardous
waste dump eventually carries unwanted chemicals into
underground sources and surface runoff pollutes reservoirs
and rivers. But people are also responsible for a
lot of the problem. For instance, if you paint your
house with an oil-based paint, clean your brushes
with paint thinner, and dump the paint thinner in
the backyard, you can contaminate an aquifer that
may be someone's water supply.
How does lead get into my drinking water?
A: Although sometimes found in natural deposits near
drinking water sources, lead contamination generally
occurs from the corrosion of lead pipes either between
the water main and a customer's home (lead service
lines) or in a home or building's plumbing system.
Even in homes not served by a lead service line, corrosive
water may cause lead to leach from lead pipes, lead
solder, and brass fixtures.
- Microorganisms in Water
Why should be a water supply tested for bacterial
A: The water may look crystal clear to the naked eye
but may harbor numerous non-visible microorganisms
in every drop. Most waterborne microorganisms are
harmless. However, a few called pathogens may cause
diseases, such as diarrhea; dysentery; gastroenteritis;
eye, ear and skin infections; and even hepatitis.
When fecal waste accidentally migrates to the water,
pathogens may be present. Once they are outside the
body, waterborne pathogens are very hard to detect.
Fortunately, coliforms are bacteria that can be readily
detected wherever waterborne pathogens are found.
Coliform bacteria typically come from the intestines
of warm-blooded animals and are considered as fecal
pollution indicators. Evidence of Coliform bacteria
in the water means there is a good chance that fecal
contamination, and therefore that waterborne pathogens
might be present. Water contamination by sewage or
excrement presents the greatest danger to public health
associated with drinking water. It has been stated
that bacteriological testing provides the most sensitive
means for the detection of such pollution.
Why are coliforms used as indicator bacteria to monitor
fecal contamination in water?
A: Various pathogenic microorganisms may be present
in water and to check each drinking water supply for
each possible pathogen would be difficult, laborious
and costly. In practice, indicator bacteria are used
instead. These are bacteria that are associated with
the intestinal tract of warm-blooded organisms, whose
presence in water indicates fecal contamination. The
most widely used fecal pollution indicators are the
Coliform bacteria. These bacteria are common inhabitants
of human and warm-blooded animals, and are generally
present in the intestinal tract in large numbers.
When excreted into the water environment, the coliforms
eventually die, but they do not die at any faster
rate than most waterborne pathogenic microorganisms,
and both the coliforms and the pathogens behave similarly
during water purification processes. Thus, it is likely
that if coliforms are found in water sample, the water
has received fecal contamination, not sufficiently
purified and may be unsafe for drinking.
Why is E-coli also used, in addition to coliforms,
as indicator bacteria to monitor fecal contamination
A: The Coliform group includes a variety of organisms
of the enteric bacteria group. It includes common
intestinal bacteria, but also few other less common
intestinal bacteria, such as Klebsiella and Enterocbacter
species. Rarely, Coliform bacteria, such as if Klebsiella
and Enterocbacter of non-fecal origin, may be present
in water that are safe for drinking. Hence, the presence
of Coliform bacteria in water, as the only indicator,
could falsely alarm. A more specific indicator is
E-coli, which belongs to the Coliform group. E-coli
bacteria originate from the intestinal tract of human
and warm-blooded animals, and from nowhere else. Therefore,
the presence of E-coli in water is considered a reliable
indication of fecal pollution.