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Water Pollution
Water pollution occurs when the quality of the water is
altered in a way that affects either the organisms living in the water
or the suitability of the water for uses such as swimming, stock
watering, and drinking.
Organic Pollutants are
usually produced by biological activity, especially during the decay of
once-living materials. Sources include runoff from barnyards and
dumps, improper disposal of human wastes, and dead plants and
animals. Other sources include gasoline and oil from automobiles
and trucks. A new class of organic pollutants has been
manufactured by man. Man-made organic compounds that do not occur
naturally are another source of organic pollutants. The
insecticide, DDT is one of these. Because DDT is not easily broken
down by natural processes, it lasts for a long time in the environment.
Inorganic
pollutants are the minerals and salts dissolved in water and the silt
suspended in water as a direct result of the actions of man. Many
of these substances are found naturally in water. The actions of
man can increase the amounts to where it is not possible to drink the
water safely. Sources include fertilizer runoff from farm fields,
sand and salt from our roads, erosion from fields and banks, ore mining,
burning fossil fuels and industrial wastes. Metals like mercury,
lead, arsenic and cadmium are also inorganic pollutants. They can
create serious health problems at very low concentrations. Sources
include industrial wastes, improper disposal of car and truck batteries,
and household products like nickel-cadmium batteries and small watch and
transistor batteries.
Biological pollutants are the
bacteria, viruses, protozoans and worms which are carried by water from
one host to another. Algae can also be a biological pollutant when
they occur in large numbers. Some of these pollutants can cause
diseases in humans and animals. "Beaver Fever", or
Giardiasis, is a well-known disease. Although it is called Beaver
Fever, it is really a human disease caused by a single-celled parasite
which lives in the intestines of humans and many other animals.
When the parasites reproduce, they form cysts which pass out of the
intestines with wastes. These cysts can live for two months in
water. If you drink water contaminated with these cysts, you can
become ill. The giardiasis parasite is removed from our water by
the filters in the water treatment plant. The disease is mainly a
problem in wilderness areas where people tend to assume that untreated
water is safe to drink or in communities that do not have effective
filtration systems. Sources of biological pollution include
treated and untreated human sewage, organic pollution, and animal waste.
Reprinted from Focus On
Water Quality (1993) with permission of Alberta
Environment.
[Biological
Properties][Chemical
Properties][Physical
Properties]
[Changing Quality][Conservation
Need][How
to Conserve]
[Effects on Organisms][Pollution][Quality][What
Can You Do?}
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