Реферат

Реферат на тему UnH1d Essay Research Paper Phosphates may be

Работа добавлена на сайт bukvasha.net: 2015-06-18

Поможем написать учебную работу

Если у вас возникли сложности с курсовой, контрольной, дипломной, рефератом, отчетом по практике, научно-исследовательской и любой другой работой - мы готовы помочь.

Предоплата всего

от 25%

Подписываем

договор

Выберите тип работы:

Скидка 25% при заказе до 21.9.2024


Untitled Essay, Research Paper

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, b


1. Диплом Контроллер угловой информации
2. Реферат на тему Harriet Stowe Essay Research Paper The woman
3. Реферат Метрология 2
4. Реферат Здравозахоронение
5. Реферат на тему Expound The Contents Of Buddhas First Sermon
6. Реферат на тему Урок по В И Далю сказка У тебя у самого свой ум
7. Курсовая на тему Основные приемы поиска материала и виды вспомогательных материалов
8. Реферат Логическая конструкция Югославской войны
9. Сочинение на тему Тютчев ф. и. - Русский поэт-философ
10. Реферат Математические методы исследования экономики 2