MSBSHSE Class 8 Science Chapter 8 Pollution Textbook Solutions

In MSBSHSE Class 8 Science Chapter 8 Pollution, students learn about the various types of environmental problems caused due to pollution. Here, we bring you the important questions and solutions of the chapter that will help students to grasp key concepts and excel in it completely.

Our subject matter experts have covered the chapter-wise explanations of important questions and solutions of MSBSHSE Class 8 Science. We hope that students can benefit from it and learn new concepts, while preparing for the MSBSHSE Class 8 2020 exam. All the important questions of the MSBSHSE Class 8 Science Solutions for Chapter 8 Pollution have been comprehensively covered. We are confident this will help students to grasp an in-depth understanding of various concepts in a simpler manner.

In this article, we have thoroughly covered all the exercise questions and added a few additional questions, along with solutions for Chapter 8 from the MSBSHSE Class 8 Science Syllabus. Students can start practising from these questions while studying this chapter and build a rock-solid foundation of concepts discussed in it, revise it before their exams and score good marks in the exams.

Maharashtra Board Class 8 Science Chapter 8: BYJU’S Important Questions & Answers

MSBSHSE Class 8 Science Chapter 8 Textbook Exercise Questions

Question 1: Following are some statements about pollution which type of pollution do those express?

a. Fog seems to be appearing in Delhi during day hours.

b. Many times, vomiting and dysentery occurs after eating ‘pani puri’

c. Problem of sneezing occurs sometimes during a visit to the garden.

d. Crop does not grow in some areas.

e. People living in the busy squares face problems like short breathing and other respiratory problems.

Answer: a. Air pollution

b. Water pollution

c. Air pollution

d. Soil pollution

e. Air pollution

Question 2: Read the passage and identify the sentences expressing types of pollution.

Nilesh is a student of std. VIII and lives in an urban area. It takes about an hour to go to the school by bus. He faces the heavy traffic of two wheelers, four wheelers, rickshaws, buses while going to school. He has been facing the problem of asthma since last few days. Doctors recommended him to stay away from the urban area. Since then, his mother sent him to the village of his maternal uncle. Nilesh saw heaps of garbage in many places in the village. Foul smell of human and animal wastes was present at many places. Blackish water with foul smell was flowing in a stream. He developed some abdominal disease within a few days.

Answer: Let’s break down the causes of pollution in the given case:

Nilesh is a student of std. VIII and lives in an urban area. It takes about an hour to go to the school by bus. He faces the heavy traffic of two wheelers, four wheelers, rickshaws, buses while going to school. He has been facing the problem of asthma since last few days: This is due to air pollution.

Doctors recommended him to stay away from the urban area. Since then, his mother sent him to the village of his maternal uncle. Nilesh saw heaps of garbage in many places in the village. Foul smell of human and animal wastes was present at many places: This is due to air and soil pollution.

Blackish water with foul smell was flowing in a stream. He developed some abdominal disease within a few days: This is due to water pollution.

Question 3: Match the pairs from ‘A’ and ‘B’ columns and explain the effect of pollution on human health.

Column ‘A’

Column ‘B’

1. Water containing cobalt

a. Mental retardedness

2. Methane gas

b. Paralysis

3. Water containing lead

c. Inflammation of lungs

4. Sulphur dioxide

d. Skin cancer

5. Nitrogen dioxide

e. Irritation of eyes

Answer:

Column ‘A’

Column ‘B’

1. Water containing cobalt

b. Paralysis

2. Methane gas

d. Skin cancer

3. Water containing lead

a. Mental retardedness

4. Sulphur dioxide

e. Irritation of eyes

5. Nitrogen dioxide

c. Inflammation of lungs

Question 4: True or false

a. Water does not get polluted by washing the clothes in running water of the river.

b. More the use of electric appliances, more will be the pollution.

Answer:

a. Water does not get polluted by washing the clothes in running water of the river. – False

b. More the use of electric appliances, more will be the pollution. – True

Question 5: Answer the following.

a. What is pollution?

b. What are pollutants?

c. What is acid rain?

d. What is the greenhouse effect?

e. Which are visible pollutants known to you ?

f. Which are invisible pollutants?

Answer: a. Pollution refers to the contamination of the natural environment that is harmful to the ecosystem. It also refers to any undesirable change in the environment that is detrimental to both living and nonliving things.

b. Pollutants are the harmful substances or chemicals that cause pollution and affect the normal functioning of the ecosystem. For example, pesticides, carbon monoxide, sulphur oxides, etc.

c. Harmful gases such as sulphur dioxide, nitrogen dioxide, etc. present in air when they combine with the water droplets present in the atmosphere form acid droplets. These droplets remain suspended in the atmosphere and fall down on earth along with rain, thereby creating an acidic effect. Such rain is known as acid rain.

d. When there is an increase in the average temperature of the surface of the earth due to the increase in the concentration of greenhouse gases such as methane, carbon dioxide, etc. this is known as greenhouse effect.

e. Visible pollutants are those pollutants which are visible to our naked eyes. For example, plant and animal wastes, sewage, pesticides, polythene bags, etc.

f. Invisible pollutants are those pollutants which cannot be seen with the naked eyes. For example, viruses, fungi, bacteria, poisonous gases such as nitrogen dioxide, carbon monoxide, etc.

Question 6: Answer the following

a. Give examples of each of water, soil and air pollution from your residential area.

b. How does the pollution occur due to vehicles? Give the names of vehicles causing least pollution.

c. What are natural reasons for water pollution?

d. Suggest four preventive measures for air pollution.

e. Explain relation between greenhouse effect and global warming.

f. Construct two slogans each on air, water and soil pollution.

Answer:

a. Sources of air pollution:

1. When fuel such as wood, kerosene, etc is burnt, it causes air pollution.

2. Harmful emissions from automobiles or vehicles on roads.

Sources of water pollution:

1. Washing dirty clothes on river banks or ponds.

2. Release of chemical wastes or domestic sewage into nearby water bodies.

Sources of soil pollution:

1. Spraying of excessive pesticides and insecticides on plants.

2. Mixing of animals wastes in plants.

b. Most of the automobiles run on fossil fuels such as diesel and petrol. These fossil fuels burn in vehicles while in use to produce energy, which results in the emission of smoke. This smoke consists of harmful gases like nitrogen oxide, carbon monoxide, hydrogen, ammonia and sulphur dioxide in it.

There are several kinds of vehicles which cause less or no pollution such as bicycle, CNG vehicles, metrorail, electric cars, etc.

c. The natural reasons of water pollution are:

1. Aquatic weeds present in water bodies deplete the oxygen level in them.

2. Excessive growth of algae.

3. When mud and sludge get mixed in water bodies due to current in rivers and their diversions.

4. Growth of harmful microbes such as bacteria and fungi on dead and decomposing matter present in the water bodies.

d. Some of the measures that should be undertaken to prevent air pollution are listed below:

(i) Use of biofuels such as CNG, LPG and lead free petrol in private and public transport.

(ii) Use of renewable sources of energy such as solar power, wind energy and hydro power.

(iii) Planting more saplings and trees to avert pollution.

(iv) Should prevent burning of dry waste and leaves in the open rather use them in composting.

e. Greenhouse gases such as carbon dioxide, methane, etc. absorb the heat of the sun and create a hole in the ozone layer of the earth and emit it back on the earth’s surface. Thus, these gases hold back the harmful sun rays and prevent them from escaping into outer space. This cycle repeats itself several times in the earth’s atmosphere and results in an optimum increase in temperature of 15°C. Therefore, greenhouse gases help to maintain the temperature on the Earth to a certain level.

However with time, the concentration of these gases have considerably increased due to increased industrialization, that has led to the heating up of the earth’s atmosphere. In due course, the overall temperature of the earth has increased, which has resulted in climatic changes. During the last century, the Earth temperature has increased by nearly 0.6°C. This has led to overall global warming.

However, the greenhouse effect can be controlled or restricted by slowing down the use of natural resources and fossil fuels. These fossil fuels produce greenhouse gases and emit poisonous gases when they burn.

f. It is an activity based question. Students are advised to do it as per their convenience.

Question 7: Classify the following pollutants into natural and manmade categories.

Sewage, dust, pollen grains, chemical fertilizers, vehicular smoke, algae, pesticides, waste of animals and birds.

Answer:

Pollutant

Category

Sewage

Man-made

Dust

Natural

Pollen grains

Natural

Chemical fertilizers

Man-made

Vehicular smoke

Man-made

Algae

Natural

Pesticides

Man-made

Waste of animal and plants

Natural

MSBSHSE Class 8 Science Chapter 8 Additional Questions

Question 1: What are the natural reasons for air pollution?

Answer: Some of the natural reasons for air pollution are listed below:

1. Volcanic eruption: Solid, gaseous and liquid materials evolve through eruption. Examples: Hydrogen sulphide, hydrogen, vapours, carbon dioxide, sulphur dioxide, ammonium chloride, dust, etc.

2. Earthquake: Poisonous gases and water vapour are released into air from inside the earth.

3. Cyclones and dust storms: Dust, garbage, soil, pollen, harmful microbes are mixed with air.

4. Forest fires: Forest fires release carbon dioxide, hydrogen sulfide, sulphur dioxide, smoke in air.

5. Microbes in air: Spores of bacteria, algae and fungi are mixed with air.

Question 2: Describe the man-made reasons for air pollution.

Answer: Some of the man-made reasons for air pollution are given below:

1. Fuel: I. Burning of fuel like coal, LPG, kerosene, petrol and diesel release carbon dioxide, nitrogen oxide, carbon monoxide, lead compounds, sulphur dioxide, etc. They cause pollution when they are released in air.

II. Burning of agricultural waste, solid waste, etc. in open space thereby causing air pollution.

2. Industrialization: Smoke releases in large quantities from several factories in the form of nitrogen oxide, sulphur powder, cotton seed powder in air.

3. Atomic energy plants and blasts: Use of radioactive elements like uranium, plutonium, thorium, graphite, etc. release radiations in air and cause pollution.

Question 3: Name some of the dangerous air pollutants which cause severe pollution.

Answer: Some of the dangerous air pollutants which cause severe pollution include sulphur dioxide (SO2), carbon monoxide (CO), nitrogen oxides, pesticides, methane (CH4), dust, particulate matter, etc.

Question 4: Describe the effects of air pollution on plants and animals.

Answer: Given below are the effects of air pollution on plants and animals:

Plants:

1. Stomata get closed and affected.

2. Slows down the photosynthesis rate in plants.

3. Growth of plants gets retarded. Leaves fall off or become yellow or discoloured.

Animals:

1. The respiration tract of animals is adversely affected.

2. Pollution causes severe irritation of eyes and skin.

Question 5: Name some biological pollutants which cause water pollution.

Answer: Some of the biological pollutants which make water unfit for drinking or are not potable due to algae, bacteria, viruses, parasites, etc. All these pollutants cause gastrointestinal diseases and spread due to biological pollution.

Question 6: What are the sources and effects of air pollutants?

Answer: Given below are some of the sources and effects of air pollutants:

Air Pollutants

Sources

Effects

1. Carbon monoxide (CO)

Industrial and vehicular smoke

Lowers the oxygen carrying capacity of blood

2. Sulphur dioxide (SO2)

Emission by factories by burning of fossil fuels such as coal and minerals

Severe irritation of eyes, blockage in respiratory tract, difficulty in breathing, chronic coughing, etc.

3. Methane (CH4)

Leakage of industrial waste

Skin cancer, asthma, respiratory disorders, etc.

4. Nitrogen oxides

Smoke emission from vehicles

Blockage in respiratory tract, lungs, difficulty in breathing, etc.

5. Pesticides

Production and use of pesticides

Mental retardation, death in extreme and prolonged exposure

Question 7: List some inorganic pollutants which cause water pollution.

Answer: Some examples of inorganic pollutants include suspended particles like fine sand, dust, soil, precipitates of salt, compounds of arsenic, cadmium, lead, mercury, and traces of radioactive material.

Question 8: What are the effects of acid rain?

Answer: Listed below are the harmful effects of acid rain to the environment:

1. Acidity of soil and water bodies happens due to acid rain. It harms the aquatic living organisms, plants and entire forest life. The total environmental ecosystem is adversely affected.

2. Erosion of buildings, metal idols, historical monuments, busts, bridges, wire fences, etc. occurs due to acid rain.

3. Heavy metals such as mercury and cadmium are absorbed by plants which enter our food chain indirectly due to acid rain.

4. Due to acidification of water in water bodies and pipes, bleaching of metal and plastic

material occurs in water and thereby giving rise to acute and serious health problems.

Question 9: Name some organic pollutants that cause water pollution.

Answer: Some of the organic pollutants are listed below:

a. Weedicides

b. Insecticides

c. Fertilizers

d. Sewage

e. Industrial effluents

Question 10: What are the man-made reasons for water pollution?

Answer: Some of the man-made reasons for water pollution are listed below:

1. Domestic sewage from villages and cities is directly disposed of in water bodies.

2. Industrial effluents such as various pigments, bleaching chemicals, leather pieces, fibres, mercury, lead, etc. are released into water.

3. Oil spillage occurs which happens while transporting or cleaning of tankers in water bodies.

4. Use of fertilizers and pesticides such as N, P, K containing chemical fertilizers, pesticides such as endrin, chlorine, etc. flow and mix with water.

5. Other valid reasons for water pollution are disposal of human wastes, washing of clothes, decomposing hemp and flax in water, disposal of ashes, floral offerings to god, water from thermal power plant, etc.

Question 11: List some of the harmful effects of water pollution.

Answer: Given below are some of the harmful effects of water pollution:

1. Effects on human beings

• Diseases like typhoid, hepatitis, skin and alimentary canal disorders.

• Ailments of liver, kidney, deformities in bones, brain, hypertension.

2. Effects on ecosystem

• Loss of plant species

• Decreased dissolved oxygen level

• Increase in salt content of water

• Retarded plant growth

• Disturbance in aquatic ecosystem

• Death of aquatic animals

• Adverse effects on seabirds

3. Other effects of water pollution

• Changes in physical and chemical properties of water

• Useful aquatic fauna is destroyed

• Soil fertility is affected

• Changes in natural color and taste

• Toxic materials are added to crops

Question 12: What do you mean by soil erosion?

Answer: Soil erosion happens when the soil is said to be polluted through the changes in its physical, biological and chemical properties and its fertility decreases due to either natural or man-made reasons.

Question 13: What are the effects of soil pollution?

Answer: Listed below are the some of the effects of soil pollution:

1. Soil fertility is reduced due to the mixing of salty, acidic water from industrial wastes.

2. Radioactive and other pollutants enter and pass through the food chain like the soil, crop, water and finally affects the human body.

3. Problem of water pollution accelerates due to soil pollution. Toxic substances leach into water and several diseases spread through complex pathogens such as bacteria, viruses, fungi, etc.

Question 14: Describe the relationship of soil pollution with air and water pollution.

Answer: When wet waste is dumped at wrong places instead of composting, pathogens grow upon it, which then mix with water causing water pollution. Insecticides, chemical fertilizers, weedicides are used in agriculture, which causes soil pollution. Use of excessively sprayed insecticides and weedicides mix with air causing air pollution.

Similarly, excessive use of chemical fertilizers also causes water pollution. Soil pollution occurs due to mixing of human wastes, birds and animals waste. This releases various stinking gases causing air pollution. When the same waste mixes with water, it causes water pollution.

Question 15: What are some of the preventive measures undertaken by the Government of India that help in pollution control?

Answer: The Government of India has enacted some major laws for prevention, regulating and controlling pollution. Given below are some laws regarding pollution control:

1. Water Pollution and Prevention Act, 1974.

2. Air Pollution and Prevention Act, 1981.

3. Environmental Protection Act, 1986.

Besides these, there are several laws and rules which are in force with respect to biomedical waste, harmful effluents, solid waste and sound pollution. Government statutory bodies such as Maharashtra Pollution Control Board and Central Pollution Control Board also supervise if the industries, industrial areas, local governing bodies like Municipalities, District Councils, Panchayat Samitis, Gram Panchayats, etc. follow the stated laws to control pollution.

We hope that the above mentioned solutions of “MSBSHSE Class 8 Science Chapter 8 Pollution” will help students to build a solid foundation of the different concepts mentioned in the chapter.

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