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Phosphates In Water Pollution


Phosphates may be created by substituting some or all of
the hydrogen of a phosphoric acid by metals. Depending on
the number of hydrogen atoms that are replaced, the
resulting compound is described as a primary, secondary or
tertiary phosphate. Primary and secondary phosphates
contain hydrogen and are acid salts. Secondary and tertiary
phosphates, with the exception of those of sodium,
potassium and ammonium are insoluble in water. Tertiary
sodium phosphate is valuable as a detergent and water
softener. The primary phosphates tend to be more soluble. 

Phosphates, which are an important component to metabolism
in both plants and animals, help in the first step in
oxidation of glucose in the body. Primary calcium phosphate
is an ingredient of plant fertilizer. 

Phosphates have caused increasing attention recently. The
focus is on the environmentally harmful effects in
household detergents. Wastewater, from laundering agents,
contains phosphates, which are said to be a water

Most laundry detergents contain approximately 35% to 75%
sodium triphosphate (Na5P3O10), which serves two purposes.
Providing an alkaline solution (pH 9.0 to 10.5) is
necessary for effective cleansing and also to tie up
calcium and magnesium ions found in natural waters and
prevent them from interfering with the cleansing role of
the detergent. 

Eutrophication is the progressive over-fertilization of
water, in which festering masses of algae's blooms, choking
rivers and lakes. Phosphorus compounds act as a fertilizer
for all plant life, whether free-floating algae or more
substantial rooted weeds, and are implicated in
eutrophication. Many countries control phosphate levels,
whereas Switzerland has banned the use of phosphates. 

The marine environment is both fragile and more resistant
than the terrestrial ecosystem. It is fragile for the
reasons that nutrients are generally present in very low
concentrations, permanently consumed by living organisms
and pollutants diffuse rapidly.
Lakes and rivers are extremely complex ecosystems.
Nutrients are taken up by both algae and rooted weeds. The
weeds act as a shelter for fish larvae and zooplankton,
both of which eat algae and are, in turn, eaten by larger
fish. Scientists have concluded that unpolluted lakes can
absorb surprisingly large amounts of phosphates without
uncertainty. When a fertilizer, such as a phosphate, is
added more algae will grow, and consequently will the
populations of zooplankton and fish. Difficulties only
arise when the lake is already impure. Zooplankton are
sensitive to their environment and many substances are
toxic to them. If any of these substances, including
phosphates, are present the zooplankton population cannot
increase. Adding phosphates to this polluted system will
case algae growth. The floating masses cut off the light
supply. Weeds die and decompose using up dissolved oxygen,
and causing sulfurous smells and plagues. Deprived of
shelter and food, the fish larvae starve. The lake is well
on the way to catastrophe. 

Without wetlands there would be a minimal amount of fresh
drinking water due to the fact that wetlands filter the
waters of our lakes, rivers and streams, sequentially
reducing contamination of water. The plant growth in
wetlands removes phosphates and other plant nutrients
washed in from the surrounding soil, consequently
restricting the growth of algae and aquatic weeds. This
growth is a serious problem in some of Canada's major
waterways, where dead and decaying algae deprive the deeper
waters of their oxygen. 

Researches at Lancaster University have studied lakes whose
plant and animal life has been killed by acid rain. The
excess acid in the lakes can be neutralized easily by
adding lime, but this makes the waters rich in calcium.
Life will gradually return to the lake but, as these lakes
should have low calcium levels, it will not be the same
kind of life that existed in lakes before pollution. The
answer, they have concluded, is to add phosphates. 

These phosphates work by shielding the water. This depends
upon nitrate ions in the lake. Contradictory, these ions
also are produced by acid rain, contain oxides of nitrogen
from combustion sources. These fertilizers do not alter the
pH level of the water. Instead, they stimulate the growth
of plants. The plants absorb the dissolved nitrates,
generating hydroxide ions, which in return neutralize the
excess acid. 

Removal of phosphates from detergent is not likely to slow
algae growth in containing substances. It may actually
prove disastrous. Its replacement with borax will
definitely be disastrous. Scientists are unsure of borax
role in plant growth. It is not required by algae and other
micro plants, but it is essential to higher plants. However
in excessive quantities, about 5 micrograms of boron per
gram of water, boron severely damages plant life. Highly
alkaline substances, gel proteins and sodium hydroxide is
hazardous substances. Another concern is the fact that each
year thousands of children swallow detergents resulting in
serious injuries or death. 

In conclusion, the only way to overcome the disastrous
effects of phosphates is to find an alternate. However, an
acceptable substitute for phosphates has not yet been
found. Washing only with synthetic detergents would require
so much detergent that the cost per wash would increase
significantly. Another alternative is the substitution of
synthetic nonionic detergents for ionic detergents in use.
Nonionic detergents are not precipitated by Calcium of
Magnesium ions. This would reduce the risk contaminating
our lakes and rivers.



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