Unit 4:-
Environment of Pollution
4.1 Pollution
Thousands of years ago, human population was small. The needs of the people were limited. Their food mostly contained natural products like fruits, vegetables and animals. At that time, environment was clean and pure. There were no industries and automobiles.
With the passage of time, human population increased. As a result of this, their needs also increased. They developed agriculture, industries and different means of transportation to meet their needs. Human has destroyed forests to cultivate the land, to build houses, roads and dams. So, these human activities badly affected the environment. As a result, the environment has become unclean and impure. This is called pollution, Pollution can be defined as: any change which occurs in the environment by the addition of unwanted and harmful materials is known as pollution. The harmful materials which pollute our environment directly or indirectly are called pollutants.
4.2 Kinds of Pollution
Air, water and land are the parts of our environment. All these parts are polluted by the addition of unwanted and harmful materials. There are three main kinds of pollution which badly affect the environment. This is all, water pollution, air pollution and land pollution.
Water pollution is the addition of harmful materials in water which change its colour, taste and smell.
Water is continuously polluted due to increase in population, industries and agricultural activities. You may have noticed that how water becomes 'dirty' after we use it for washing clothes and bathing, etc. Like this when harmful substances such as sewage, toxic chemicals, silt, and fertilizers etc.When mixed with water becomes contaminated.
The substances,that contaminate water is called water pollutants.
When the atmosphere is contaminated by harmful substances such as smoke and dust particles which effect the living and non living things, it is called as air pollution The substances which contaminate the air are called air pollutants The sources of air pollutants are factories, power plants, automobile exhausts, burning of wood and dung canker etc.
When the land is contaminated with fertilizers, pesticides, insecticides and polythene bags, it is called as land pollution.
4.3 Causes of Water, Air and Land Pollution
There are some main causes of water, air and land pollution.we discuss them one by one.
4.3.1 Causes of Water Pollution
Industrial and sewage wastes are continuously adding to water bodies such as rivers, canals, streams and oceans. Highly toxic materials present in these wastes cause water pollution.
When water goes underground and passes through the populated areas, untreated. sewage water and wastes mix with it and pollute it.
Oil tankers and petroleum refineries are responsible for oil leakage in sea water. Due to this, sea water becomes polluted.
The more use of insecticides and chemical fertilizers in the crop fields also cause water pollution. Such chemicals are washed into the rivers by rain water and cause the water to become polluted.
4.3.2 Causes of Air Pollution
Burning of fossil fuels like coal, petroleum etc.He was one of the major by Causes of air pollution. When these fuels are burnt, poisonous gases and harmful substances are released into air.
Due to incomplete combustion of fuel in automobile, poisonous gases such as carbon monoxide and nitrogen oxide are emitted in the air.
Use of insecticides, pesticides and fertilizers in agricultural activities emit hazardous chemicals like ammonia in air.
Exhaust from factories, industries and oil refineries releases large amount of toxic chemicals like carbon monoxide and hydrocarbons in the air.
5:- Between the mining process, dust and chemicals are released in the air causing massive air pollution.And it is very dangerous
By the burning of garbage and plastics, poisonous gases are produced which badly affect the living organisms.
Volcanoes, dust storms and forest fires also cause air pollution.
4.3.3 Causes of Land Pollution
The rubbish such as waste papers, plastics, tins, tyres and polythene bags pollute the soil.
People dispose off the factory wastes, urban and rural household garbage here and there. Because of the lack of proper waste disposal facilities, soil becomes polluted.
More use and improper disposal of polythene bags cause serious problems in the sewerage and water disposal system.
4.4 Effects of Water, Air and Land Pollution on Environment
There are some serious effects of water, air and land pollution on environment. We discuss these one by one.
4.4.1, Effects of Water Pollution
Polluted water contains bacteria causing different diseases such as diarrhea, typhoid, cholera, and dysentery etc.
Sewage water produces bad smell due to the presence of gases like ammonia and hydrogen sulphide.
Fish and other aquatic creatures cannot live in the polluted water.
4.4.2 Effects of Air Pollution
1. Respiratory and heart problems
Toxic chemicals and gases in the air create several respiratory and heart diseases along with cancer. Children are more likely suffer from pneumonia and asthma.
II. Global warming
Due to air pollution, our Earth is becoming hotter day by day. It is called global warming. The rise in temperature is very harmful for life.
iii. Acid rain
Harmful gases like nitrogen oxide and sulphur oxide are released into the air during the burning of fossil fuels.These air pollutants react with the rain water and make it acidic This rain falls on the ground in the form of acid rain. Acid rain causes great damage to humans, animals, crops and buildings.
iv. Depletion of Ozone layer
Ozone gas is present in the atmosphere. It is responsible for protecting living organisms from harmful radiations of Sun. Due to the addition of different harmful chemicals into atmosphere, ozone layer becomes thin and unable to stop the harmful radiations of Sun. As a result, these radiations directly come to the Earth's surface and cause skin and eye diseases. These radiations also damage the crops.
v. Smdg
Smog is a type of air pollution. It is formed due to smoke produced by heavy transportation and industries in big cities.
4.4.3 Effects of Land Pollution
Polythene bags dropped here and there can pack up the mouths of water and sewerage pipes. Sometimes, the animals eat these bags and die.
Different types of fertilizers, insecticides, pesticides also become deposited in soil. They decrease its fertility and pollute it. Plants cannot grow in polluted soil. Crops also cannot be grown in it.
4.4.4 Ways to reduce Air Pollution, Water Pollution andLand Pollution
Due to following ways, we can reduce air pollution, water pollution and land pollution:
Reducing Air Pollution
We should use solar, wind and geothermal energy as far as possible instead of burning fossil fuels like coal and petroleum etc.
We should reduce the use of insecticides, pesticides and fertilizers in the field of agriculture. We should manure as far as possible.
Garbage and plastics etc. Should not burn in the open Air.
Release of dust and chemicals during mining process be controlled or reduced as far as possible.
Release of exhaust from factories, industries and oil refineries be reduced as far as possible.
We should encourage people to use more and more public transport instead of cars and other vehicles.
We should use energy efficient devices such as energy savers as far as possible.
Reducing Water Pollution
We should avoid adding industrial and sewage wastes to water bodies such as rivers, canals, streams and oceans etc.
We should avoid more use of insecticides and chemical fertilizers in the crop fields.
We should avoid adding untreated sewage water in the populated areas of villages and cities.
Reducing Land Pollution
We should not drop polythene bags, tyres, tins, waste papers and other rubbish here and there.
We should reduce using of chemical fertilizers, insecticides and pesticides in crop fields as far as possible.
We should reuse and recycle the used materials.
