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Class 11 Environment Chapter 5 Environmental Pollution
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Environmental Pollution
UNIT – 5
ENVIRONMENTAL STUDIES
Textual Questions and Answers
1. What do you mean by environmental pollution? Name the different types of pollution.
Ans: The term pollution have derived from latin word pollute. Pollute means make dirty. Thus pollution means a change in the physical, chemical and biological aspects of environment. This pollution is very harmful to human life and all other living beings.
Different types of pollution :
(i) According to environment: When different segments of the environment are affected by pollution, they may be categorized as
(a) Air pollution
(b) Water pollution
(c) Soil pollution
(ii) According to pollutant: pollution caused by pollutants may be of different types such as
(a) Thermal pollution
(b) Noise pollution
(c) Radioactive pollution
(d) Solid waste pollution
(e) Oil pollution
(f) Industrial pollution
(g) Marine pollution
2. What is air pollution? Identify the sources of air pollution.
Ans: The presence of pollutants in air which is the cause of injury and damage to human beings, animals, plants and other objects is called air pollution.
The sources of air pollution are:
(i) Natural sources :
(a) Volcanic eruption: Releasing poisonous gases like SO₂, H₂S₂CO etc.
(b) Forest fires : In the areas of tropical region throughout the year forest fire is a common feature. very large quantities of smoke and particulate matter are released during their breakout.
(c) Natural organic and inorganic decays or vegetative decays. methane gas, carbon dioxide are released into the air
(d) Dust: Dust is always present in the atmosphere in varying amounts.
(e) Pollen grains of flowers: PollutioN is also caused by the production of pollens in the spring season.
Pollens or aeroallergens enter the atmosphere form weeds, grasses and trees. They are mainly responsible for causing allergy.
(f) Fungal spores: Micro-organisms such as algae, fungi, bacteria, yeasta, rusts spores etc are present as variable particles in the atmosphere.
(g) Radioactive materials: The radioactive minerals present in the earth crust and action of cosmic rays from outer space on gaseous constituents of the atmosphere are mainly responsible for radioactivity of the atmosphere.
(ii) Man made sources :
(a) Deforestation
(b) Burning of fossil fuels
(c) Emission from vehicles
(d) Rapid industrialization
(e) Modern agricultural practices
3. Mention few effects of air pollution on human health.
Ans: Few effects of air pollution on human health-
| Air pollutant | Sources of production | Effects on man |
| 1.Sulphur-dioxide | Coal & oil combustion constriction. | Causes chest pain headache, vomiting, death from respiratory ailments |
| 2.Nitrogen Oxides | Soft coal & automobile exhausts, unvented gas stove, kerosene heaters, wood stoves Inhibits cilia action so that soot and dust penet rate far into the lungs | Headache,drowsiness, irritated lungs, children’s colds |
| 3.Carbon monoxide | Burning of coal, gasoline, motor exhausts, faulty furnaces, unvented gas stove, kerosene heaters, wood burning | Causes nausea, reduces oxygen carrying capacity of blood, headache, drowsiness irregular heartbeat |
| 4.SPM ash, soot smoke etc. | Incinerators & every manufacturing processes | Causes eye irritation, emphysema, cancer |
| 5.Hydrogen sulphide | Refineries, chemical industries, bituminous fuels | Causes nausea, irritation of eyes and throat |
| 6.Ammonia | Explosives, dye making fertilizer plants passages | Inflames upper respiratory |
| 7.Phosgene or carbonyl chloride | Chemical and dye making | Induce coughing irritation and fatal pulmonary edema |
| 8.Aldehydes | Thermal decomposition of oils, fats or glycerol | Irritate nasal and respiratory tracts |
| 9.Suspended particle | Incinerators and almost every manufacturing process | cause emphysema, eye irritation, cancer |
| 10.Asbestos | Pipe insulation, vinyl ceiling floor tiles | Lung diseases, lung cancer |
Q.4 what is water pollution ? What are the effects of water pollution on human health?
Ans: When water contains substances more than it is wanted or t contains harmful elements, germs or particles, then the water is called polluted water. The physical and chemical properties of such water is substantially different from pure water. The degree of difference indicates the degree of pollution.
The effects of water pollution on human health are:
(i) Typhoid : Salmonella typhi
(ii) Cholera: vibrio cholerae
(iii) Dysentery: shigella
(iv) Diarrhea: cryptosporidium
(v) Giardiasis: giardia lamblia
(vi) Diarrhea: e coli
(vii) Gastroenteritis: viruses
(viii) Polia: polioviruses
Contamination of drinking water, either directly or indirectly by sewage and other wastes or by human or animal excrement is to most common and widespread danger associated with water quality problem particularly in the underdeveloped world. Faecal pollution leads to introduction of a variety of intestinal pathogens bacteria, virus and parasites causing diseases starting from mild gastroenteritis to severe and fatal dysentery, cholera or typhoid When drinking water is contaminated with sewage, gastroenteritis and infectious hepatitis may occur in epidemic proportion. Other diseases like rashes, fever, myocarditis, meningitis, respiratory diseases etc. are also likely. Protozoic diseases like amoebiasis, giardiasis may also occur through sewage contamination of water sources.
5. What is soil pollution? How it can be controlled?
Ans: Decrease in soil fertility because of addition of some foreign elements is called soil pollution. Soil is polluted with dumping of solid wastes generated in the household and manufacturing units.
Control of soil pollution :
(a) Industrial effluents should be properly treated before discharging them into the soil.
(b) Solid wastes should be properly segregated as biodegradable and non biodegradable wastes at source and than disposed off by adopting effective scientific methods.
(c) Use of bio-fertilizers instead of chemical fertilizers should be encouraged.
(d) Application of pesticides should be controlled.
(e) Bioremediation can be adopted for degradation of toxic chemicals present in soil.
(f) Necessary enactment of laws should be made for panel action against those who are involved in polluting soil.
(g) Awareness should be created among people.
6. What are solid wastes? How are they classified.Give examples.
Ans: Higher standard of living of ever increasing population has resulted in an increase in the quantity and variety of waste generated. Solid wastes, i.e. the wastes other than liquid or gaseous wastes can be classified as municipal, industrial, agricultural, medical, mining waste and sewage sludge.
Urban waste consists of
(i) Domestic waste containing a variety of discarded materials, like, polythene bags, empty metal and aluminium cans, scrap metals, glass bottles, waste paper, food waste etc.
(ii) Waste from shops mainly consists of waste paper, packaging material, cans, bottles, egg shells, tea leaves etc.
(iii) Biomedical waste includes anatomical wastes, pathological wastes, infectious wastes etc.
(iv) Construction/demolition waste includes debris and rubbles, wood, concrete etc.
(v) Horticultural waste and waste from slaughter houses include vegetable parts, residues and remains of slaughtered animals etc.
Industrial waste consists of a large number of materials including fac tory rubbish, packaging material, acids, alkalis and metals etc. During some industrial processing, large quantities of hazardous and toxic mate rials are also produced. The main sources of industrial wastes are chemical cal industries, metal and mineral processing industries. Radioactive wast are generated by nuclear power plants. Solid wastes from other types of industries include plastic, paper, glass, wood, oils, paints, heavy, metala asbestos, batteries etc.
7. Discuss the environmental effects of solid wastes.
Ans: The environmental effects of solid wastes are:
(i) Open dumps are malodorous places in which disease carrying vermins such as rats and flies proliferate.
(ii) Methane gas is released into the surrounding are due to decomposition of solid waste by microorganisms.
(iii) Liquid that oozes and seeps through solid waste heap ultimately finds its way into the soil, surface water and ground water.
(iv) Hazardous materials dissolved in the liquid contaminate underground water and soil strata.
(v) Solid waste is highly heterogeneous and is not segregated at any stage. It includes wastes from industries, hospitals and nursing homes, domestic waste etc.
(vi) The leachate consisting of a variety of chemical constituents, seeps and pollute the ground water.
(vii) Absence of landfill liners aggravate the problem.
(viii) Health hazards faced by the residents living in the nearby areas of dumping sites can not be ignored.
(ix) The present practice of collecting solid waste from individual houses results in wastage of time and thereby increases the cost of collection.
(x) Transportation of collected solid wastes openly by the tractors or trucks is unhygienic and the aesthetic look of the city is also affected.
8. What are the major greenhouse gases? What is effect?
Ans: The major Green House Gases are Carbon Dioxide, Methane, Nitrous Oxide, Chlorofluorocarbons (CFCs), Water vapour and Ozone.
Green House Effect: The carth is the only planet in our solar system that supports life. The evolution of life on earth was possible because of the presence of a unique set of environmental conditions viz. water, oxygen rich atmosphere, land and a suitable surface temperature. The earth has an atmosphere of proper thickness and chemical composition. About 30% of the incoming energy from the sun is reflected back to spece while the rest (70%) reaches the earth, warming the air, water, land and maintaining an average surface temperature at about 150C. During the day, energy from the sum (largely in the visible part of the spectrum) is absorbed by the earth’s surface. If all this energy were to be absorbed t completely, the earth would gradually become hotter. But in reality, the earth both absorbs and simultaneously releases energy in the from of infrared radiations (long wavelength, less energetic). All the rising heat is not lost to space, but is partly absorbed by some gases present in the atmosphere in very small quantities, called the Green House Gases (GHGs),
9. What do mean by global warming? Mention few consequences of global warming.
Ans: Due to the greenhouse effect, the average surface temperature of the earth is at about 15°C and the earth becomes hospitable to a variety of life forms. If the GHGs do not perform this function, most of the energy would escape, leaving the earth cold (about-18°C) and the earth would become unfit to support life. Heat trapped by the greenhouse gases in the atmosphere keeps the planet warm enough to allow us and other species to exist. But due to different natural as well as anthropogenic activities the concentration of the greenhouse gases in the atmosphere has increased during the past several decades. Scientists estimate that the earth’s average temperature has increases by 0.3-0.6°C since the beginning of the last century. Ever since the industrial revolution, began 150 years ago, manmade activities have added significant quantities of greenhouse gases to the atmosphere. The atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased by about 31%, 171% and 17% respectively between 1750 and 2000 (IPCC,2001) The rise in temperature due to the blanketing effect of increased level of greenhouse gases is termed as global warming.
Few consequences of Global Warming are :
(i) Climate change
(ii) Depletion of ozone layer (Greenhouse effect)
(iii) Acid Rain
10. What is acid rain?
Ans: Oxides of sulphur and nitrogen originating from industrial operations and fossil fuel burning are the major sources of acid forming gases in the atmosphere. When sulphur dioxide and nitrogen oxides are transported by prevailing winds, they come in contact with water vapour and form sulphuric acid and nitric acid respectively, droplets of sulphuric acid and small particulates of sulphates and nitrates. These chemical substances come down to the earth’s surface in two forms-wet (as acid rain, snow, fog and cloud vapour etc) and dry (as acidic particles). The resulting mixture is called acidic deposition or commonly called acid rain.
VERY SHORT TYPES QUESTION & ANSWER MARKS:
1. Who is most responsible for environmental pollution?
Ans: Man.
2. What happened in the USA in 1962-65?
Ans: The USA experienced in severely dry climate and bitter cold in 1962-65.
3. What happened in UK during 1961-62?
Ans: The UK experienced drought and erratic climate in 1961-62.
4. What did Russia suffer in 1971?
Ans: Russia suffered extremely low temperature in 1971.
5. What natural calamity happened in India in 1978?
Ans: India was badly affected by flood in 1978.
6. When drought badly affected India.
Ans: In 1980, drought badly affected India.
7. When did the industrial revolution take place?
Ans: Towards the end of 18th century, the industrial revolution took place.
8. What is abnormal climate?
Ans: When pollution occurs in the environment abnormal changes occur in the climates also. This is called abnormal climate.
9. Why do floods occur in Assam every year?
Ans: Deforestation and the unplanned construction of embankments are the main causes of floods in Assam.
10. Describe the atmosphere of Guwahati city.
Ans: The atmosphere of Guwahati is also very much polluted by the smoke, ashes, garbages and population. The motor vehicles and population are mostly responsible for environmental pollution in Guwahati.
11. What is the full form of SMP?
Ans: The full form of SMP is Suspended Particulate Matter.
12. When and where did the industrial revolution take place?
Ans: The industrial revolution took place in 18th century in Europe.
13. What is the full form of MIC?
Ans: The full form of MIC is Methyl Isocyanate.
14. Write the name of the most populous city of India.
Ans: Kolkata is the most populous city of India.
15. How do the jet planes also pollute the atmosphere?
Ans: The jet planes release aerosol in the upper layer of the atmosphere and pollute the atmosphere.
16. Which agent is the most responsible for air pollution?
Ans: Motor vehicle is the most responsible for air pollution.
17. When did the government of India enforce air pollution act?
Ans: The government of India enforced the Air Pollution Act in 1981.
18. What are the causes of lung cancer and bronchitis?
Ans: The SPM and sulphur-di-oxide are the causes of lung cancer and bronchitis.
19. Which elements damages our blood circulation system, liver and kidneys?
Ans: Air-born lead damages our blood circulation system, liver and kidneys.
20. What is personal air pollution?
Ans: When air pollution affects the health of an individual person it is called personal air pollution.
21. Which elements create acids rain?
Ans: Sulphur oxides and nitrogen oxides create the acid rain.
22. Write the name of the famous forest of Germany destroyed by acid rain.
Ans: Black rest.
23. What is the most sophisticated technology to get rid of impurities in water?
Ans: The effluent treatment plant is the sophisticate technology to get rid of impurities in water.
24. What is the full form of ETP?
Ans: The full form ETP is Effluent Treatment Plant
25. What is the full form of DDT.
Ans: The full form of DDT is Dichloro-diphenyl-trichloro-ethane.
26. Name the worst elements that disturb the ecosystem.
Ans: The destruction of forests and increasing population are the worst elements that disturb the ecosystem.
27. In which century did the industrial revolution take place?
Ans: Towards the end of 18th century the industrial revolution took place.
SHORT & LONG TYPES QUESTION & ANSWER MARKS:
1. Describe the reasons of changes in weather and climate?
Ans: There are many natural and man-made reasons of changes in weather and climate. But men are more responsible than the nature. The burning of fossil fuels, the rapid population growth, destruction of forest etc. are the main factors of environment pollution. These are the main reasons of changes in weather and climate.
2. Describe what happened to the climate of the world during the second half of the last century.
Ans: During the second half of the last century, we found many changes in climate. In 1962-65, the USA had the experience of a severely dry climate and bitter cold, in 250 years. The UK had the experience of the coldest climate in 1961-62. Europe also suffered drought in 1976. Russia suffered the extremely low temperature in 1971.
3. How do the changes in climate affect the people in the developing counties?
Ans: The developing countries are generally located in the monsoon regions. For the climatic changes the monsoon shows the erratic behaviour in these regions. As a result, heavy floods or drought occur. In the developing countries most people depend on agriculture. If the floods or drought occur every year, that means heavy damaged to the crops. The irregularity of monsoon also affects the crops and the life of the people. In this way the climatic changes affect the people in the developing countries.
4. What did happen to the Brahmaputra and Barak valleys in the second half of the last century?
Ans: Since the second half of the last century, there have been heavy floods in the Braghmaputra and Barak valleys of Assam. Severe drought conditions also occurred. So the floods and drought are perennial problem of Assam. For the climatic changes, the south-west monsoons are very irregular in this regions and there is scanty of rain.
5. Discuss the abnormal climatic conditions of the world.
Ans: For the natural and mad-made factors some abnormal behaviour have been observed in nature. In 1962-65, the USA had the experience of a severely dry climate and bitter cold. The UK had experienced the coldest climate in 1961-62. Drought and erratic climate were the main features of Europe in 1976. Russia had experienced the extremely low temperature in 1971. Destruction of forests and tropical rain forest are the causes of abnormal climate.
6. Discuss the main causes of climatic changes.
Ans: For climatic changes both the nature and man are responsible. But man are more responsible than the nature. The rapid growth of population, deforestation, excessive use of natural resources, burning of fossil fuels, increasing industries are the main causes of climatic changer
7. Why do floods occur in Assam so often?
Ans: In Assam the rainfall is decreasing and even then the floods occur every year. Deforestation and unplanned construction of embankments are the main causes behind the rise of river-beds and consequently floods occur frequently.
8. Write short notes on the following:
(a) Tropical region
Ans: Equator divides our earth into northern and southern hemispheres The nearby areas of the equator on both sides are under the Tropical region. For the climatic changes the tropical regions are badly affected.
The countries of the tropical region now face many problems. But the floods and droughts are the major problems for them.
(b) Polar regions
Ans: Our earth has two poles-north pole and south pole. These are called polar regions. The polar regions are called water reservoirs, because the polar regions are always covered with thick ice. At present the scientists are concerned about the global warming. If the global warming increases, the ice of the polar regions will melt, and floods will occur almost all over the world.
(c) The Himalayas
Ans: The Himalayas are the highest mountain range of the world. It is also water, reservoir, because many parts of the Himalayas are covered with thick ice. Many big rivers of India come out from the Himalayas. So if the global warming increases, the Himalayas will supply more water to the river, and floods will occur in many places.
(d) Fossil fuel.
Ans: The remains of organisms embedded in the surface of the earth, contain high carbon and hydrogen. Those elements are used by man as fuel. This kind of fuel is called fossil fuel.
(e) Acrosol.
Ans: Aerosol is fine solid or liquid particles in the atmosphere which exert a lot of influence on the other gases including sulphur-di-oxide. It exists in air in the form of smoke, fog and vapour. It is very harmful for our atmosphere.
(f) Minamata disease:
Ans: The water polluted with mercury may causes many a disease. One such disease occurred first in the Bay of Minamata in Japan. So this disease is called Minamata disease.
(a) Mercury:
Ans: Mercury is a poisonous substance. Use of mercury has been increasing rapidly as it is required especially in paper mills and electrical industries. Some other industries also use mercury. Now the production rate of Mercury in the world is about 9,000 tones per year. The water polluted with mercury may cause many diseases in aquatic and other animals.
(h) Hould-hold-waste :
Ans: Cowdung, carcasses of cattle, dogs, cats, goats and other animals, excreta, of various animals, lumps of straw and hay, various types of vegetable wastes, litters etc. are called house-hold wastes. These house hold wastes also pollute the water.
(i) Traffic Control:
Ans: Noise created by automobiles can be reduced by banning blowing of hors and permitting only such vehicles which have good bodies and efficient silencers, Restriction on heavy vehicles to ply on certain routes during the peak hours of traffic will also reduce the adverse effects of noise pollution.
(j) Noise free zones :
Ans: The areas near hospitals and educational institutions should be declared as noise free zones. Frequent movement of vehicles, blowing of horns and use of loudspeakers should be restricted.
(k) Sources of noise :
Ans: Industries, factories, electric looms, generators, stone crushers, trains, motor vehicles, construction of building and bridges, loudly playing radio, TV, stereo are the sources of noise.
(l) Plantation :
Ans: Planting of trees is called plantation. Plants absorb noise. So in cities and towns, there should be green belts. Plantation of trees makes the towns or cities beautiful and makes the climate pleasant.
9. How do the developing countries hamper the ecosystem? Discuss.
Ans: The rate of population growth is higher in developing countries than the developed countries. People pollute the air and destroy the forests for more cultivable lands. The rapid increase of population also hamper the progress of the developing countries and leads to poverty and undue interference on the activities of the ecosystem. In this way the developing countries hamper the ecosystem.
10. Discuss, how the climatic changes, hamper the progress of the developing counties?
Ans: Generally the developing countries are located in the monsoon regions. The monsoons greatly influence the lives of the people. Most of the people depend on agriculture and agriculture depends on monsoon.
But for the climatic changes, the monsoon shows an erratic behaviour in those regions. As a result every year floods or droughts take place in those regions and hamper the crops.
The monsoons come sometimes early, sometime late and sometimes they show uncertain behaviour.
In this way the climatic changes hamper the progress of the developing countries.
11. “Urban areas are most responsible for environmental pollution”. Discuss
Ans: The industries, factories etc. are mostly established in city or towns. The industries, factories etc. burn the fossil fuels and release a large amount of smokes and ashes to our environment. There are plenty of motor vehicles which burn the petrol, diesel etc and produce a plenty of smoke and ashes and pollute the atmosphere. The urban areas generally provide more opportunities for earning livelihood. So the people come to the towns or cities. The people also pollute the air. In some cities or towns many forests are also destroyed for their own projects. For these reasons urban areas are responsible of environmental pollution.
12. What is ‘Green House Effect’? Discuss.
Ans: Industries, factories and motor vehicles burn the fossil fuels and pollute our atmosphere. The polluted air contains carbon-di-oxide, carbon monoxide, methene, lead, aerosol etc. These elements allow the sun rays to fall on earth and on the other hand, traps the outgoing radiation from t the earth. In this way these elements help to increase global warming e This phenomenon is called ‘Green House Effect.
13. What are the air polluting substances released in India?
Ans: Sulphur-di-oxide, carbon-di-oxide, hydrocarbons, hydrogen sulphide, SMP and lead particles are the polluting substances released in e India.
14. What is ‘smog’?
Ans: Nitrogen oxides and hydrocarbons form a layer at high temperature in our atmosphere, it is called smog. It is a grey or yellowish f brown opaque substance deposited in air.
15. What is air pollution? What are its categories?
Ans: The presence of pollutants in air which is the cause of injury and damage to human beings, animals, plants and other objects is called air pollution.
Air pollution is of three categories. These are-personal, occupational and community air pollution.
16. ‘Nature also pollutes air’ – Explain.
Ans: Air pollution is also caused by nature itself. It may be due to respiration from man and animals, dusts, bacteria, fungi, pollens, spores, volcanic gases etc. So it is said, ‘nature also pollutes air.
17. Describe the extent of air pollution in some major cities of the world.
Ans: The air of some industrial cities are always covered with smog. An aerial view of the cities like London, Tokyo, New York etc. shows that these cities are covered with thick smog. Excessive burns of petrol, diesel, coal etc. produce the harmful gases like carbon-di-oxide, nitrogen oxide and sulphur-di-oxide and they pollute the air. The rapid urbanisation, deforestation, land erosion are also the causes of air pollution.
18. Can air pollution be rooted out entirely? How can it be controlled?
Ans: No, the air pollution cannot be rooted out entirely.
The air pollution can be controlled as follows:
(a) We should reduce burning fossil fuels and think for alternative fuels.
(b) We should change our old technology and industrial equipments.
(c) The government should strictly enforce the law of pollution.
(d) We should use purified fuel in our motor vehicles.
(e) Plantation of trees is also a good method to control air pollution.
19. Describe the legal and organisational aspects of controlling air pollution.
Ans: The government of India has enacted a law in 1981 to control and prevent the air pollution. This act is implemented by central pollution control board and state pollution control boards. Thus government organisations are now handling the law of pollution to control air pollution.
20. What is the best way to minimise air pollution?
Ans: The best way to minimise air pollution is to replace the old s technology and the equipments of industries, factories, motor vehicle s etc. and think for new anti-pollution devices.
21. Discuss the major causes of air pollution.
Ans: The major causes of air pollution are:
(a) We burn excessive fossil fuels in industries, factories and motor vehicles and produce a huge amount of harmful gases and smoke and pollute the air. M
(b) The rapid growth of population pollute the air.
(c) The rapid urbanisation, deforestation, land erosion etc, also pollute the air.
22. What are the sources of water pollution?
Ans: There are many sources which are responsible for water pollution Among them eroded soils, decomposed body of plants and animals, fallen leaves, organic materials, chemical fertilizers, industrial wastes, municipal and house-hold wastes are the main sources of water pollution.
23. How does mercury pollute water?
Ans: Some industries use mercury compounds. Mercury has been increasing through paper mills and electrical industries. When this poisonous compound mixes with water, it causes many diseases in our body. In this way the mercury pollute water.
24. How do ships carried crude oil pollute the sea water?
Ans: When crude oil is carried by ships across seas and oceans, some crude oil spills to the seas owing to leakage and other reasons. This spilt crude oil spreads over wide area forming a scum. Crude oil neither dissolves in water nor evaporates. It remains in water for a very time and pollute the sea water which is very harmful for marine lives.
25. How did mercury compound cause Minamata disease?
Ans: The industries dumped mercury compound on the shore of the Minamata Bay of Japan. This poisonous compound pollutes the water. Fish were affected by the polluted water and the inhabitants of Minamata Bay consumed those fishes as food and this disease occurred there. In this way the mercuric compound caused Minamata disease.
26. Describe how seas and oceans are polluted?
Ans: The polluted water of towns, cities and agricultural fields flows through the rivers and their tributaries to sens and pollute the sea water.
The crude oil spreads in seas and oceans through the leakage of huge til tankers carrying oil. This crude oil is neither dissolved in water nor evaporated. It remains in water for a long time and pollutes the water and affects the marine lives.
27. Explain how the water drawn from wells may be harmful
Ans: The rivers and their tributaries carry the poisonous substances to the sea. These substances may go down the earth’s crust and pollute the underground water, which we use for our drinking. So the water drawn from wells may also be harmful for our health.
28. How are the aquatic lives affected by pollution?
Ans: The nutrients in the lakes, river, seas etc. help algne and weeds to grow under water luxuriantly. They consume large amount of oxygen and exhaust the stock of oxygen and create a dearth of oxygen in sea water which greatly hamper the aquatic lives. In this way the aquatic lives are affected by pollution.
29. What is environment?
Ans: Environment means surrounding, we are surrounded by abiotic and biotic factors of environment. The various types of radiation, air, water, rocks etc, form the abiotic environment. Living organisms that interact among themselves form the biotic environment.
30. What does environment sciences provide us with?
Ans: Environment science provides us with an approach towards Understanding the environment of our planet. It also tells us about the impact of life on it and vice-versa. It also makes us to enquire for the solutions to environmental problems that confront mankind now.
31. What special position does the earth enjoy in the solut system?
Ans: The special position of the earth in the solar system is that it is the only planet that supports life. The cuvironment of the earth is conduct for the existence, growth and development of living beings.
32. What is solar system? How many planets are there in it? While is the planet that supports life?
Ans: The sun and its family of nine planets along with their satellites is the solar system. There are nine planets in it. The earth is the only planet that supports life.
33. How does environment affect life on earth?
Ans: Environment affects the size, shape and colour of plants animals and the ways in which they grow and live, Environment is responsible for survival of any particular organism. We get food, clothing and other things necessary for our survival from environment.
34. Mention some of the uses of water?
Ans: Water is essential for sustaining life. Water is also used for bathing washing cleaning, irrigating crop lands, generating electric powers, running factories and for many other service.
35. Write briefly about Hydrosphere?
Ans: Hydrosphere includes all water bodies on earth. The occans, seas, rivers, ponds etc, are all parts of it. Oceans and seas cover 7.1% of the hydrosphere. Only 0.04% is frets water usable by man and other i animals. Water is not as scarce as petroleum oil and coal because it is reusable.
36. Why is water not like coal or petroleum oil? Or, How is water different from coal and oil?
Ans: Coal and petroleum oil exhaust for ever once they are used. They cannot be savvied or recycled once they are burnt on the other hand water remains more or less at the same level due to water cycle prevailing on earth.
37. Write a short note on Lithosphere?
Ans: Lithosphere is the hard surface of the earth which accounts for 29% of the total surface area on the globe. It is the crust of the earth and it is made up of old rocks and minerals mixed up with various substances. It provides habitat to all kinds pf plants, animals and microorganism.
Lithosphere holds human civilization and all that man has made.
38. What are the divisions of our environment?
Ans: On the basis of its physical characteristics our environment is divided into:
(a) Lithosphere (land or soil)
(b) Hydrosphere (water bodies)
(c) Atmosphere (air)
(d) Biosphere (Plants and animals)
39. What is the importance of air?
Ans: Air is essential for all living beings in the biosphere. Man cannot live even for few seconds without air. He breathes 22000 times a day and inhales 16 Kg. of air from the atmosphere. Air is the store house of oxygen for man and other living beings and of carbon dioxide for trees and plants without air there will be no rain, cloud, and snow, fog etc.
40. How would you explain water cycle?
Ans: Water moves in the atmosphere in cyclic order. Water cycle begins with the evaporation of oceans, seas, rivers, lakes and all other water bodies. Evaporation occurs due to sun heat. The vapour forms cloud in the sky and then comes down to earth in the form of raindrops hail stones, dewdrops and snowfall etc.
41. What is atmosphere and why is it necessary?
Ans: The gaseous cover that surrounds the earth on all sides and controls life on it is called atmosphere. It protects earth’s surface from becoming too hot. It filters the solar radiations and prevents the harmful ultra violet rays from reaching the earth’s surface.
42. What are the main sources of air pollution?
Ans: Air pollution occurs when pollutants are released into air. Ulle main air pollutants are automobile exhaust, industrial smoke, solvent and radioactive radiation and particulates.
43. What is smog? What harm does it do?
Ans: The word smog has been formed of smoke and fog. Smog IS a thick layer of Smokey fog that floats over cities Smog has occurred over London, Glasgow, Delhi, Chennai, Kolkata. About 3.500 to 4000 people had died in the London smog of 1952. Smog causes respiratory trouble leading to slow but painful death.
44. Write a short note on solvents?
Ans: Solvents are used in paints, polish and sprays. The use of paint, polish etc have been increasing Accordingly the use of solvent too is increasing steadily. The spray materials remain suspended in air for a long time and are very harmful to man. Pesticides and insecticides contain solvent. They pollute air in rural areas.
45. What is particulates and what do they do?
Ans: Particulates are commonly Known as SPM (Suspended Particulate Matter). They consist of both solid and liquid tiny particles. They include dust, mist, spray, smoke, fumes etc. Normally chimneys in factories and power plants pour them out. Particulates create respiratory problem in human beings.
46. What is ozone layer? What is its function?
Ans: Ozone layer is a gaseous layer in the atmosphere. It exists about 30 to 60 km above the surface of the earth. It is like an umbrella that protects the living beings and plants from the dangerous and harmful Ultra Violet Rays.
47. Who detected the ozone a hole? What colored it?
Ans: A British Antarctic Survey Team reported 40% loss in ozone layer. They detected it in 1985. Scientists after study found that the new threat, the hole in the ozone layer was caused by a chemical called CFC (Chloro Fluoro Carbon), which is used in modem personal care products, and Refrigerators.
48. Write a note on Greenhouse and its usefulness.
Ans: Green house is made of glass. It is used for growing plants. During winter season in the cold countries the insulation is not sufficient for plant growth. The green house allows visible sunrays to enter into it, but prevent the infrared rays to go out. Thus gradual warming up takes place inside the green house favouring growth of the plants.
49. What green house effect?
Ans: The green house effect means a progressive warming up of the earth’s surface due to blanketing effect of man made carbon dioxide and some other gases in the atmosphere, with the increasing accumulation of carbon dioxide in the atmosphere global temperature will increase gradually.
50. What will be the effect of global warming?
Ans: If temperature riser gradually as a result of global warming the glaciers will melt, the level of the water bodies like sea and ocean will rise and many low lying areas will be submerged. The marine ecosystem will be damaged affecting all aquatic life.
51. What is acid rain? What causes it?
Ans: When rain water contains acid, it is called acid rain. Pollutants like oxide of sulphur, nitrogen an carbon remain accumulated in the atmosphere. Rain water dissolve them and transforms them into weak acids and the drops finally come down to earth in the fortify of acid rain. Amount of acidity depends on the accumulation of the gases mentioned above.
52. What are the effects of acid rain?
Ans: Acid rains are the main cause of deaths of lakes for which it is called lake killers. Acid rain kills aquatic lives including plants and animals. It destroys the mineral elements and other nutrients of soil and adversely affects production. It also affects human beings and building etc. and other structures.
53. What are the major water pollutants?
Ans: When water becomes unfit for drinking or supporting life due to degradation of its quality it is called polluted. Industrial wastes, home sewage, run off from mining area or crop field, hot water from power plants, oil and radioactive wastes are the major water pollutants.
54. Show how oil pollutes water?
Ans: Oil tankers sailing in sea, sometimes develop leakage or sometimes they meet with accidents. As a result oil flows down to the surface of the sea water off. Shore drilling also releases some amount of oil into sea water. The oil spreading in sea water affects birds other aquatic life. Feathers of aquatic birds are socked in oil and they die soon.
55. How does power plants pollute water?
Ans: Fresh water flow is needed in power plants. Water-cools down the steam condensers. After cooling the condensers the hot water is released into water bodies, which changes the temperature of the water. This is called thermal pollution. Changes in temperature of water can harm fish populations.
56. Write a note an earth’s environment.
Ans: “Environment means surrounding. We remain surrounded by various types of radiations, air, water, soil rocks and minerals which form the abiotic factors of the environment. We live interacting with them similarly we remain surrounded by historic environment consisting of living organisms. We live reacting with them and we are inter related with them. Environment affects size, shape and colour of plants and animals.
The environment may also be responsible for survival of S9me certain organisms. We get our food, clothing and shelter from our environment. Man also lives in a cultural environment. He lives surrounded by things he has made. Among the nine planets in the solar system only the earth has an environment that can life. It is earth’s environment that has made the existence, growth and development of living beings. Based on its physical characteristics of earth’s environment are divided into: Lithosphere, Hydrosphere, Atmosphere and Biosphere. Biosphere supports life and it is related to other three spheres.
57. Write a note an Hydrosphere.
Ans: Hydrosphere is the water bodies an earth, 71% of one planet is covered by the oceans and seas 96.5% of the total water on earth is found in the seas and oceans, 1.76% of the total water is there in the ice caps and glaciers. 1.70% is the ground water. Only the balance 0.04% is fresh water. Fresh water is found in the rivers, lakes and streams, Fresh water is not abundant. Still we do not feel scarcity of water.
Because water is not exhaustible source like coal or petroleum oil. Water cycle on earth keeps the water level almost steady. Water cycle, begins with evaporation of sen and ocean water under the heat of sun. The vapour sails in the sky in the form of cloud and then comes down to earth as raindrops, dew, fog or snow. Water is an essential life-supporting element on earth. Besides drinking, water is used for bathing, cleaning, irrigating. and generating electric power and so on. Much ancient civilization flourished on riverbanks mainly because of the water streams.
58. Write a note on atmosphere.
Ans: The atmosphere is a gaseous cover surrounding the earth. It preserves life on earth. The atmosphere protects life on earth by way of filtering the sunrays. It prevents the harmful ultra violet rays of the sun from coming to earth’s surface. Air is essential for all types of life in the biosphere. Man cannot survive even for few seconds without air. A man breathes 22000 times a day inhaling 16 kg of air from atmosphere. Oxygen in the air is essential for man and animals while carbon dioxide is essential for trees and plants. Air is the reservoir of both oxygen and carbon die oxide and many other gases. Without air there will be no wind, clouds, fire and rain on earth. Air is a mechanical mixture of several gases. It contains 78.084% nitrogen, 20.95% oxygen, 0.93% argon and 0.03% carbon dioxide.
59. Write a note on environmental degradation.
Ans: Thousands of years ago the primitive men depended on nature for his food, drinks and shelter. They hunted in forests, fished in water and ate wild fruit and thus satisfied their simple needs. Population grow thore and society developed, man changed the natural habitat to villages,towns and cities, railways, highways, factories and industries were established with this change from started the process of environment pollution or degradation.
Not only man natural forces also pollute environment. Earthquake, volcanic eruptions, land-slide, floods etc degrades environment. Nature has her own system of recovering minor environment degradation. When exploitation of Nature by man is unlimited nature fails to recover. The earth has been facing serious environmental problems during the previous three decades. Increase in population, spurt in technology aided by mans greed to get more and more things have polluted air, water and soil. The atmosphere is so much polluted now that t it has paused a threat to mankind and other living beings. Unless something
is done urgently environmental degradation may endanger all life on earth.
60. Mention some of the measures to be adopted for controlling air pollution.
Ans: The following measures should be adopted for controlling air pollution:
(a) The engines of the automobiles should be redesigned the emissions at minimum level.
(b) Steps should be taken for
(i) regular servicing of the vehicles.
(ii) use of filters.
(iii) replacement of old engines and parts by new one.
(iv) proper tuning-ups of the engines should be done.
(c) Industries should be located at a safe distance from the residential areas.
(d) TraditiOnal use of fire-wood, coal etc.should be minimized and smoke-free devices should be used. Forest fires also should be ‘Checked
(e) Without implementation of pollution control system, industries should not be accorded permission for production.
(f) There should be greenbelt around towns, townships and villages. Also there should be green belt around industries.
(g) Railways should use electric engines instead of coal or steam engines.
(h) There should be strict provision of law regarding pollution control in case of automobiles and industries.
61. What is water pollution? Suggest some of the measures for controlling water pollution.
Ans: When water becomes unfit for drinking or supporting life due to degradation of its quality. It is said to be pollution. The industrial wastes, home-sewage, run-off from mining area or crop fields, hot water from power plants, oil and radioactive wastes are the major water pollutants.
Following measures are to be adopted for controlling water pollution:
(a) There should be strict regulations by Government to the effect that no industry can release industrial wastes into rivers or streams without proper treatment in the effluent treatment plant. Production should not be permitted without the establishment of the treatment plat.
(b) Domestic and other sewage should be treated in sewage treatment plant, and only after such a treatment it should be allowed to be discharged into water bodies.
(c) Use of chemical pesticides and fertilizers should be limited and only herbal pesticides should be used.
(d) There should be complete ban an disposal of dead bodies of man and animals into rivers. River banks should be kept clean.
(e) Aquatic plants should be cleared at short intervals. shorti
(f) Water should be kept purified from harmful micro organisms by using potassium permanganate.
(g) Above all people should be made aware about the harmful effect of water pollution. So that they learn to protect themselves from water borne diseases.
62. Describe, how the Cosmic Rays pollute our environment?
Ans: One naturally occurring radiation is the cosmic radiation of cosmos mays. These rays come from extraterrestrial sources. These rays are composed of numerous high moving particles and high energy radiation with gamma rays. So when the cosmic rays fall on earth and induce radioactivity on some elements like carbon, tritium and beryllium. As the cosmic rays induce radioactivity, it may pollute our atmosphere.
63. “Now-a-days man has been artificially producing radiation of various types. Cite examples in support of the statement.
Ans: Man can tolerate the less ionizing radiations. But with the advent of time, man has been artificially producing gradations of various types out of necessity in different fields and use the harmful rays also. Scientists discovered x-rays and have used x-rays in diagnosis and research. Gamma rays are also used in treatment of diseases, in industries, in agriculture and food preservation. Similarly man has used ultraviolet and infrared radiation and also microwave,
64. Name four heavy elements.
(a) Uranium
(b) Thorium
(c) Radium
(d) Plutonium.
Ans: The four heavy elements are:
65. Describe the effects of radiation on environment?
Ans: The effects of radiation on environment are very dangerous.
These may divided into two:
(a) Immediate effect: The immediate effect which reveals itself in burn injury, loss of hair, impairment of bone, bone marrow, leukaemia, cancer, foetal abnormality, foetal death, abnormal birth, and immediate death of the victim.
(b) Delayed effect: The delayed effect is usually detectable after years. One of such effects is gene mutation. This is of serious nature, for it affects the future generations.
66. What do you mean by radioactive substance? Name the radioactive radiations.
Ans: Uranium, Radium Thorium and Polonium are heavy elements. These elements are used to produce nuclear energy and weapons. These elements namely Uranium, radium polonium and thorium are called the radioactive substance.
Radioactive radiations are of three types-Alpha, beta and gamma.
67. State the nature of the radioactive radiations.
Ans: There are three types of radioactive radiations-alpha, beta and gamma. Alpha is positively charged parties, beta is negatively charged particles and gamma is not particles but electromagnetic waves of very short wave length.
68. How does a nuclear fission bomb and its radioactive fallouts affect the environment?
Ans: When the nuclear fission bomb is exploded, the radioactive materials start moving afloat in the sky and form dense dark clouds. These clouds then spread out within a few hours. But two or three weeks later they extend up to several hundred kilometres of the space in the sky and pollute the atmosphere. They not only pollute the air but gradually they pollute both the land and water. In this way the nuclear bomb and in radioactive fallouts affect the environment.
69. Explain how radioactive radiations may affect the future generation.
Ans: During the Second World War, USA dropped nuclear bombs on Hiroshima and Nagasaki of Japan. But after about more than 50 years, abnormal and deformed children are being born even now and this because of radioactive radiation. So we find that the radioactive radiation is very harmful to our future generation.
70. Most of the noises are man-made. Explain.
Ans: Any of our works creates some noise. Most of the originate crise primarily from industries, factories and transports. Modem civilization creates more and more noise. Noise inside many factories become hazard to health.
Heavy machines of industry or factory furnaces, powerlooms, generators, compressors, grinding mills etc. are the industrial sources of noise pollution
Transport like heavy diesel vehicles, trains, motorcars, three wheelers. two wheelers, aeroplanes, jet crafts etc. are the prime sources of noise pollution. That is why most of the noises are man-made.
71. Mention a few sources of sound are which have intensity harmful to human health.
Ans: A siren makes a noise of 150-160 decibels, an aeroplane makes 120-140 decibels, a jet aircraft makes 140 decibels, a factory makes 110 decibels, horn of vehicles make 95 decibels and heavy truck makes 90 decibels. If any of these sounds, lasts for more than four hours at a stretch,it can effect our whole body. It can also affect us mentally and physically.So such kinds of noise are very harmful to us and our environment.
72. What is noise? What do you mean by noise pollution?
Ans: The unpleasant and unwanted sound is called noise. Too much noise pollutes the environment. It is also no less harmful than air or water pollution. At present a noise pollution has become serious problem to us.
73. Describe the sources that produce noise.
Ans: Every work we do creates noise. Industries, factories, electric looms, generators, stone crushers, trains, motor vehicles, three wheelers, two wheelers, aeroplanes, jet planes, construction of buildings and bridges, playing radio, TV, stereo etc. with high volume of sound creates noise.
74. Describe how noise pollution affects human organs.
Ans: Noise above 80-120 decibels causes hearing impairment and total deafness. Excessive noise causes hypertension, heart trouble, giddiness, fatigue and insomnia. A sudden or prolonged noise may damage our eardrums.
75. Describe the measures that can be taken for controlling noise pollution.These are as follows:
Ans: There are several measures for the control of noise pollution.
(a) General awareness.
(b) Noise reduction at source
(c) Suggestions from expert bodies
(d) Traffic control
(e) Noise-free zone
(f) plantation
(g) Enforcement of law.
76. Discuss the laws and acts enforced by the government of India to control noise pollution.
Ans: The government of India have enforced many acts and laws to control noise pollution. These are Motor Vehicle Act of 1939, Aircraft Act of 1934, the Factory Act of 1948 and the Indian Penal Code, No. 268.
77. What are the main causes of deforestation?
Ans: Following are the main causes of deforestation:
(a) Fuel crisis.
(b) Opening of new farming land for food and cash crop.
(c) Demand for residential areas for growing population.
(d) Demand for timber and grazing land
(e) Industrial and commercial demand.
78. Mention the factors responsible for the decrease of soil quality.
Ans: Decrease in the quality of soil is caused due to:
(a) Accelerated rate of soil erosion.
(b) Decrease in plant nutrients.
(c) Decrease in soil microorganisms.
(d) Excess or deficit of moisture content.
(e) High fluctuation of temperature.
79. How does sewage and other domestic waste pollute the land and ground water?
Ans: The sewage sludge contains appreciable concentration of toxic heavy metals. When used continuously for irrigation, metals like zinc.nickel, chromium, lead etc. accumulate in the soil and pollute the land and subsequently find their way to the ground water and pollute it too.
80. What are the causes of waterlogging? Can it be averted?
Ans: Unplanned construction of embankments, roads, railway lines, lack of proper drainage and sewage system, and excessive irrigation are the causes of waterlogging Yes, it can be averted by constructing the roads, railway lines, embankments in scientific method. The drains should also be constructed in scientific method.
81. Describe the role of microbes in sustaining the quality of solid and helping the plants grow.
Ans: Soil is made of dust, sand, clay and organic substances. Many minute organism are found in soil, these are microbes. Microbes enrich the soil and make it fertile.
Plants cannot absorb dissolved food in the soil unless it is broken into tiny parts by microbes. Without the microbes, the plants would have not survived. In this way the microbes helping the plants grow.
82. Why is Surat the cleanest city?
Ans: Surat was the dirtiest city in India which was infested with rodents and plague had been a great menace. But the Municipal Corporation now spends huge amount of money to clear the garbage. So it is now the cleanest city in India.
83. Enumerate and explain the factors responsible for degradation of land.
Ans: There are four factors responsible for degradation of land. These are:
(a) Action of wind and rainfall
(b) Waterlogging
(c) Chemical fertilisers and pesticides
(d) Garbage.
84. Discuss how strong winds and heavy rainfall degrade the land?
Ans: The green cover of earth’s surface protect the land from outer effects. Roots of plant bold the soil particles tightly and make it compact. But when the forest cover is removed the soil becomes less compact and strong wind can blow off apart of it.
The rain water also can easily wash away. Such soil and deposit in rivers, ponds or lakes. In this way the winds and heavy rainfall degrade the land.
85. What do you mean by deforestation? What are its effects?
Ans: Destruction or removal of forests by denudation is called deforestation.
For deforestation the drought and flood occur severely. Deforestation causes of soil erosion. Deforestation disturb the ecological system of our environment.
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