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1.       Water pollution

Water pollution is any chemical, physical or biological change in the quality of water that has a harmful effect on any living thing that drinks or uses or lives /in/ it. When humans drink polluted water it often has serious effects on their health . Water pollution can also make  unsuited for the desired use.

What are major water pollutants ?  There are several classes of water pollutants. The first are disease – causing agents. These are bacteria , viruses, protozoa and parasitic worms that enter sewage systems and untreated waste.

A second category of water pollutants is oxygen demanding wastes: wastes that can be decomposed by oxygen – requiring bacteria. When large populations of decomposing bacteria are converting these wastes it can deplete oxygen levels in the water. This causes other organisms in the water , such as fish , to die.

A third class of water pollutants is water soluble inorganic pollutants , such as acids , salts and toxic metals. Large quantities of these compounds will make  water unfit to drink and will cause the death of aquatic life.

Another class of water pollutants are nutrients ; they are water – soluble  nitrates and phosphates  that cause excessive growth of algae and other water plants, which deplete the water’s oxygen supply. This kills fish and when found in drinking water, can kill young children. Water can also be polluted by a number of organic compounds such as oil, plastics and pesticides , which are harmful to humans and all plants and animals the water. A very dangerous category is suspended sediment, because it causes depletion in the water ‘s light absorption and the particles spread slanderous compounds such as pesticides through the water.

Finally, water soluble radioactive compounds can cause cancer, birth defects and genetic damage and are thus very dangerous water pollutants.

Where does water pollution come from?

Typical rainwater has a pH of about 5 to 6. This means that it is naturally a neutral, slightly acidic liquid. During precipitation rainwater dissolves gasses such as carbon dioxide and oxygen. The industry now emits great amounts of acidifying gasses such as sulphuric oxides and carbon monoxide. These gasses also dissolve in rainwater. This causes a change in pH of the precipitation - the pH of rain w8oo fall to a value of or below 4. When a substance has a pH of below 6.5, it is acid. The lower the pH, the more acid the substance is. That is why rain with a lower pH, due to dissolved industrial emissions, is called acid rain.

Why does water sometimes smell like rotten eggs?

When water is enriched with nutrients, eventually anaerobic bacteria, which do not need oxygen to practice their functions, will become highly active. These bacteria produce certain gasses during their activities. One of these gasses is hydrogen sulphide. This compounds smells like rotten eggs. When water smells like rotten eggs we can conclude that  there is hydrogen present, due to a shortage of oxygen in the specific water.

What causes white deposit on showers and bathroom walls?

Water contains many compounds. A few of these compounds are calcium and carbonate. Carbonate works as a buffer in water and is thus a very important component. When calcium reacts with carbonate a solid substance is formed, that is called lime. This lime is what causes the white deposit on showers and bathroom walls and is commonly known as lime deposit. It can be removed by using a specially suited cleaning agent.

Water pollution

Water pollution occurs when a body of water is adversely affected due to the addition of large amounts of materials to the water. The sources of water pollution are categorized as being a point source or a non-source point of pollution. Point sources of pollution occur when the polluting substance is emitted directly into the waterway. A pipe spewing toxic chemicals directly into a river is an example. A non-point source occurs when there is runoff of pollutants into a waterway, for instance when fertilizer from a field is carried into a stream by surface runoff.

Types of water pollution

Toxic substance – A toxic substance is a chemical pollutant that is not a naturally occurring substance in aquatic ecosystems. The greatest contributors to toxic pollution are herbicides, pesticides and industrial compounds.

Thermal pollution – Thermal pollution can occur when water is used as a coolant near a power or industrial plant and the is  returned to the aquatic environment at a higher temperature  than it was originally. Thermal pollution can lead to a decrease in the dissolved oxygen level in to water while also increasing the biological demand of aquatic organisms for oxygen.

Ecological Pollution- ecological pollution takes places when chemical pollution, organic pollution or thermal pollution  are caused by nature rather than by human activity. An example of ecological pollution would be an increased rate of siltation of a waterway after a landslide which would increase the amount of sediments in runoff water. Another example would be  when a large animal , such as a deer, drowns in flood and a large amount of organic material is added to the water as result . Major geological events such as a volcano eruption might also be sources of ecological pollution.

Specific sources of water pollution.

Farming;

Farm often use large amounts of herbicides and pesticides, both of which are toxic pollutants. These substances are particularly dangerous to life in rivers , streams and lakes , where toxic substances can build up over a period of time.

Farms also frequently use large amounts of chemical fertilizers that are washed into the waterways and damage the water supply and the life within it. Fertilizers can increase the amounts of nitrates and phosphates in the water, which can lead to the process of europhication.

Allowing livestock to graze near water sources often result in organic waste products being washed into the waterways. This sudden introduction of organic material increases the amount of nitrogen in the water, and can also lead to eutrophication.

Four hundred million tons of soil are carried by the Mississippi river to the Gulp of Mexico each year. A great deal of this siltation is due to runoff from the exposed soil of agricultural fields. Excessive amounts of sediment in waterways can block sunlight, preventing aquatic plants from photosynthesizing, and can suffocate fish by clogging their gills.

Business:

·         Clearing of land can lead to erosion of soil into the river

·         Waste sewage generated by industry cab get into the water supply, introducing large organic pollutants into the ecosystem.

·         Many industrial and power plants use rivers, stream and lakes to despose of waste heat . the resulting hot water can cause thermal pollution. Thermal pollution can have a disasterous effect on life in an aquatic ecosystem as temperature increases decrease the amount of oxygen in the water, thereby reducing the number of animals that can survive there.

·         Water can become contaminated with toxic or radioactive materials from industry, mine sites and abandoned hazardous waste sites.

Acid precipitation is caused when the burned of fossil fuels emits sulfur dioxide into the atmosphere. The sulfur dioxide reacts with the water in the atmosphere, creating rainfall which contains sulfuric acid. As acid precipitation falls into lakes, streams and ponds it can lower the overall PH of the waterway, killing vital plant life , thereby affecting the whole food chain. It can also leach heavy metals from the soil the into the water, killing fish and other.

Introduction

Comprising over 70% of the Earth’s surface, water is undoubtedly the most precious natural resource that exists on our planet. Without the seemingly invaluable compound comprised of hydrogen and oxygen, life on earth would be non-existent: it is essential for everything on our planet to grow and prosper. Although we as humans recognize this act, we disregard it by polluting our rivers, lakes, and oceans. Subsequently, we are slowly but surely harming our planet to the point where organisms are dying at a very alarming rate. In addition to innocent organisms dying off, our drinking water has become greatly affected as is our ability to use water for recreational purposes. In order to combat water pollution, we must understand the problems and become part of the solution.

Causes of pollution

Many causes of pollution including sewage and fertilizers contain nutrients such as nitrates and phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae. Excessive growth of these types of organisms consequently clogs our waterways, use up dissolved oxygen as they decompose, and block light to deeper waters. This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability of fish and other invertebrates that reside in water. Pollution is also caused when silt and other suspended solids, such as soil, wash off plowed fields, construction and logging sites, urban areas, and eroded river banks when it rains. Under natural conditions, lakes, rivers, and other water bodies undergo Eutrophication, and aging process that slowly fills in the water body with sediment and organic matter. When these sediments enter various bodies of water, fish respiration becomes impaired, plant productivity and water depth become reduced, and aquatic organisms and their environments become suffocated. Pollution in the form of organic material enters waterways in many different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots and pastures. When natural bacteria and protozoan in the water break down this organic material, they begin to use up the oxygen dissolved in the water. Many types of fish and bottom-dwelling animals cannot survive when levels of dissolved oxygen drop below two to five parts per million. When this occurs, it kills aquatic organisms in large numbers which leads to disruptions in the food chain.

Additional forms of water pollution

Three last forms of water pollution exists in the forms of petroleum radioactive substances, and heat. Petroleum often pollutes water bodies in the form of oil, resulting from oil spills. The previously mentioned Exxon Valdez is an example of this type of water pollution. These large-scale accidental discharges of petroleum are an important cause of pollution along shore lines. Besides the supertankers, off0shore drilling operations contribute a large share of pollution. One estimate is that one ton of oil is spilled for every million tons of oil transported. This is equal to about 0.0001 percent. Radioactive substances are produced in the form of waste from nuclear power plants, and from the industrial, medical, and scientific use of radioactive materials. Specific forms of waster are uranium and thorium mining and refining. The last form of water pollution is heat. Heat is a pollutant because increased temperatures result in the deaths of many aquatic organisms. These decreases in temperatures are caused when a discharge of cooling water by factories and power plants occurs.

Demonstrators Protest drilling

Oil pollution is growing problems, particularly devastating to coastal wildlife.  Small quantities of oil spread rapidly across long distances to form deadly oil slicks. In this picture, Demonstrators with “oil-covered” plastic animals protest a potential drilling project Key Largo, Florida.  Whether or not accidental spills occur during the project, its impact on the delicate marine ecosystem of the coral reefs could be devastating.

Oil Spill clean up

Workers use special nets to clean up a California beach after an oil tanker spill. Tanker spills are an increasing environmental problem because once oil has spilled , it is virtually impossible to completely remove or contain it. Even small amount spread rapidly across large areas of water. Because oil and water do not mix , the oil floats on the water and then washes up on broad expanses of shoreline. Attempts to chemically treat or sink the oil may further disrupt marine and beach ecosystem.

Classifying water pollution

The major sources of water pollution can be classified as municipal, industrial, and agricultural. Municipal water pollution consists of waste water from homes and commercial establishments. For many years , the main goat of treating municipal waste water was simply to reduce its content of suspended solids, oxygen – demanding materials, dissolved inorganic compounds , and harmful bacteria.

1.    What are causes of the water pollution in big cities?

2.    What are causes of water pollution in Mongolia?

3.    What kind of water pollution in the world?

4.    What do you think Mongolian water pollution?

5.    When was the World water’s day celebrated in the first time?