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Phosphates


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Phosphates Essay, Research Paper

Phosphates

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 pollutant.

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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