Pollution Class 10 ICSE — Selina Concise Chapter 15

Pollution class 10 ICSE biology explains how air, water, and land lose their natural quality. This Selina Concise chapter 15 covers five types of pollution, their sources, and their effects. It also describes radiation, noise, and the control measures available. This page walks through the chapter section by section, in the book’s own order, so you can follow along with your textbook open.

Download Pollution Class 10 ICSE Biology Chapter 15 PDF

Download the Pollution Class 10 ICSE Biology chapter PDF from the Selina Concise textbook to revise offline or print for practice. It is the full chapter as printed in the book — 8 pages, 21 sections, 23 questions.

What is inside Chapter 15

8 pages · 21 sections · 23 exercise questions

• PROGRESS CHECK: 4 questions
• PROGRESS CHECK: 1 questions
• PROGRESS CHECK: 2 questions
• PROGRESS CHECK: 3 questions
• PROGRESS CHECK: 13 questions

15.1 POLLUTION

Pollution is the addition of a constituent to air, water, or land that deteriorates the natural quality of the environment. A pollutant is that constituent itself. The two terms are different. Pollution is the condition of degradation. A pollutant is the specific substance causing it.

The chapter names five major types of pollution. Each type has different sources and effects on living things and the environment.

The first progress check asks whether pollution and pollutant are the same. They are not. A pollutant is the substance added. Pollution is the resulting harm to the environment.

15.2 AIR POLLUTION

Air pollution means degradation of air quality that harmfully affects living organisms and certain objects. The chapter divides it into two types.

• Gaseous pollution: harmful gases from a variety of sources.
• Particulate pollution: particles such as dust, smoke, mining debris, stone-drilling dust, and worn rubber from motor-vehicle tyres.

Natural sources include ash from volcanoes, dust from storms, and forest fires. These are beyond human control. Man-made sources are vehicles, industries, garbage, and brick kilns. These four are largely under human control, and methods to limit them are being developed.

Vehicles running on petrol and diesel release three main gaseous pollutants in their exhaust: \mathrm{CO}_{2}, \mathrm{SO}_{2}, and CO. Rubber tyres wear down and release particles. Speeding vehicles also lift road dust into the air. The book’s Fig 15.1 shows the particulate and gaseous emissions from an automobile.

Control measures include efficient engines, good quality automobile fuels, lead-free petrol, and greater use of compressed natural gas (CNG).

15.2.2 Industrial Air Pollution

Industries range from small pottery and carpet-weaving units to huge sugar factories, cloth factories, metal factories, automobile plants, drug manufacturers, and oil refineries. All give out pollutants of various kinds.

The chief industrial gaseous pollutants are \mathrm{CO}_{2}, \mathrm{SO}_{2}, CO, and oxides of nitrogen. Factory chimney smoke carries many particulate pollutants. Stone drilling and mining of coal and metals produce fine particles that pose serious health hazards to labourers.

Smog is smoke plus fog. Smoke mixes with dust particles and small drops of fog to form it. Smog harms plants. If inhaled, it can cause asthma and allergies in humans.

15.2.3 Burning Garbage

Household garbage mainly contains vegetable and fruit peelings, dry-fruit shells, washings of pulses and rice, and food leftovers. These materials have two possible fates.

One option is composting, which means making manure for agricultural use. The other is burning in special enclosures. Burning releases \mathrm{CO}_{2} and other harmful gases. The smoke adds to particulate air pollution.

15.2.4 Brick Kilns

Brick kilns are fire-heated enclosures for making construction bricks. In Hindi, they are called “eenton ke bhatte”.

The process works like this. Raw moist clay bricks are arranged in heaps with firewood between them. A layer of special mud mixture covers the set-up to contain the flames. This is left for a few days. The smoke collecting inside is released through a hole. When opened, the original mud-coloured bricks have turned red, and a huge quantity of ash remains.

The wastes are large quantities of ash and broken brick bits. These are pollutants, either reused somehow or just dumped. The smoke and heat given out are also pollutants.

15.3 WATER POLLUTION

Water pollution means any change in water quality that makes it unsuitable for use by humans and other living organisms. The chapter lists five major sources.

• Household detergents
• Sewage
• Industrial wastes
• Oil spills
• Thermal pollution

To recall these five in order, use the mnemonic “Dirty Sewage Is Often Toxic”. Each capital letter stands for one source: Detergents, Sewage, Industrial waste, Oil spills, Thermal.

15.3.1 Household Detergents

Every home uses detergents, which are cleansing agents, to wash soiled garments, crockery, and utensils. The dirty water flows down drains and becomes a source of water pollution.

A common mistake is thinking detergents are safe cleansers. The progress check on the following page tests this. Detergents do contribute to water pollution.

15.3.2 Sewage

Sewage is the liquid waste from domestic activities. It consists of kitchen wastes, toilet waste, and other household waste water.

Most cities have sewage treatment plants. These remove the dirty part and release cleaned water into nearby rivers or water bodies. Small towns and villages may still release their fluid wastes directly into a nearby river or lake.

The book also notes certain practices that add to pollution. Disposing of dead bodies in rivers, and immersing cremation ashes in rivers like the Ganga, are sources of water pollution.

15.3.3 Industrial Waste

Many industries, both small and large scale, produce waste water containing chemical pollutants. This waste is commonly discharged into rivers.

Fish processing industries set up near sea coasts release toxic wastes into the sea, causing pollution there.

15.3.4 Oil Spills

Oil spills are the accidental discharges of petroleum in oceans or estuaries. The sources are overturned oil tankers, offshore oil mining, and oil refineries.

Oil pollution kills a lot of marine life, including fish and birds. The book’s Fig 15.3 shows a duck coated with oil after a spill.

15.3.5 Thermal Pollution

Many industries use water for cooling their machinery. Thermal power plants, oil refineries, and even nuclear power plants do this. The hot waste water may be 8–10°C warmer than the intake water.

This hot water is released into nearby streams, rivers, or the sea. The warming harmfully affects animals, even killing fish, and harms the plant life growing in the water.

Worked example. Suppose a factory draws cooling water from a river at 22°C. It returns the water at 31°C. The rise is 9°C, which sits inside the book’s stated 8–10°C range. The warmer water released back into the river warms the surrounding water. This warming harms the animals living there, can kill fish, and damages plant life growing in the river.

A progress check question asks whether hot water discharged into water bodies affects fish. The correct answer is that it does. Hot discharge water is harmful to aquatic life.

15.4 SOIL POLLUTION

Soil pollution is largely localised. Air and water pollution can spread over long distances, but soil pollution stays where the contaminant lands.

The major sources of soil pollution are:

• Industrial wastes
• Urban commercial and domestic waste
• Chemical fertilizers
• Biomedical waste
• Pesticides

To recall these five, use the mnemonic “I Use Compost Before Pesticides”. Each capital letter stands for one source: Industrial waste, Urban waste, Chemical fertilizers, Biomedical waste, Pesticides.

15.4.1 Industrial waste

Industries release gaseous air pollutants and chemical-laden water. They also give out solid wastes. These solids come as chemical residues, flyash, and metallic ash.

A common confusion appears in the progress check: flyash and metallic ash are industrial waste, not urban domestic waste. The two are different categories of soil pollution.

15.4.2 Urban Commercial and Domestic Wastes (“Urban”: Relating to Cities)

Cities and towns have a variety of markets. Food grains, vegetables, and fruits are sold there. Tailors, restaurants, and banquet halls also produce solid waste in different forms.

At home, people generate plastic bags, glass bottles, electric bulbs, kitchen waste, and paper packaging. All of this is solid waste.

Municipal workers collect it for disposal. Part of it can be converted into manure. The rest goes to sanitary landfills, where waste is dumped in a ground depression and covered with dirt every day.

15.4.3 Chemical Fertilizers

Chemical fertilizers include nitrates, phosphates, and ammonium salts. They help crops grow faster and increase yield. But excessive use is harmful.

Rain water slowly washes these fertilizers into lakes and ponds. There, bacteria grow faster. The bacteria consume a lot of oxygen in the water. This leads to the death of fish and other water animals.

15.4.4 Biomedical Waste

Biomedical waste includes numerous items:

• Needles, syringes, dirty dressings
• Unused discarded medicinal tablets and powders
• Discarded biological research materials carelessly placed in municipal garbage

Such waste often reaches the soil. It can harm soil organisms. It can also reach humans indirectly through certain agents.

15.4.5 Pesticides

Pesticides such as DDT were widely used to kill pests in farms, godowns, and homes. Most persisted undegraded in the environment, causing harm to life indirectly. Milder pesticides are now used, but even these are pollutants.

DDT, or dichloro-diphenyl-trichloroethane, alters the basic structure of soil. It kills microorganisms that recycle nutrients in the soil. It can even reach the human body through food grown in such soil.

The wastes from all pollution sources fall into two categories:

Sorting example. A hospital discards an empty glass bottle, leftover cooked rice, a plastic syringe, and vegetable peels. The rice and peels are biodegradable. The glass bottle and plastic syringe are non-biodegradable. This sorting is exactly what the progress check asks you to do with medical wastes.

15.5 RADIATION

Radiation is a form of energy consisting of high-energy particles. It is used extensively in medicine, such as X-rays, and in nuclear power plants for generating electricity.

X-rays carry a great deal of energy. They damage body cells. Too frequent or too many X-ray exposures can cause serious health hazards. These include damaged chromosomes, genetic variations, and bone cancer. X-ray machine operators must take special care to avoid exposure.

Nuclear power plants can leak radiation through negligent disposal of wastes or accidental explosion. Two serious plant explosions have occurred. The Chernobyl disaster struck Ukraine in 1986. The Fukushima Daiichi plant in Japan failed on 11 March 2011. Many people died and many more suffered radiation exposure, causing health problems such as haemorrhaging and cancers.

The chief radiation pollutant was Iodine-131, which raises the risk of thyroid cancer. Radiation even leaked into the sea and reached humans passively through seafood.

Carelessly discarded radioactive material caused damage in Mayapuri, Delhi, in 2010. Radioactive waste containing Cobalt-60 from a research centre reached market streets through scrap dealers. Several exposed people suffered and some died. One sufferer kept Cobalt-60 pencils in his back pocket and suffered serious burns.

15.6 NOISE POLLUTION

Noise is defined as any unpleasant or loud undesired sound that interferes with hearing and concentration. Major sources include industrial machines, workshops, trains, automobiles on the streets, and jet aircraft landing and taking off. Loud conversation, radios or televisions inside houses, loudspeakers, and musical bands in public places also contribute.

Noise is relative. If you are reading seriously or solving a mathematical problem, even a mild conversation in the room becomes noise. But if you are doing light reading in a running train, you may not be disturbed at all.

Harmful effects of noise pollution:

• Interferes with communication
• Interrupts concentration and disturbs peace of mind
• Lowers efficiency of work
• Disturbs sleep and leads to nervous irritability
• A sudden loud sound can damage the eardrum; prolonged noise can cause deafness
• Bird life gets disturbed by aircraft landing or taking off from airports

Measures to minimise noise pollution: prohibit blowing of horns, restrict loudspeakers especially at night, plant trees by roadsides, keep doors closed to reduce noise reaching our ears, and avoid burning firecrackers.

15.7 EFFECTS OF VARIOUS TYPES OF POLLUTION

Pollution affects the environment, humans, and other life in many ways. The chapter groups the significant effects into two categories: effects on human health and effects on climate and environment.

Effects on human health. Air pollution causes respiratory problems and lung disorders. Particulate lead may cause a shortage of blood cells. Smog leads to asthma and poor visibility. The exhaust gas \mathrm{SO}_{2} causes serious damage to the air passages in the lungs, producing bronchitis. Water pollution may lead to cholera, jaundice, and typhoid. Soil pollution may indirectly affect human health through pesticides used in farming.

Effects on climate and environment. The three most significant are acid rain, the greenhouse effect with global warming, and ozone layer depletion.

Acid rain. Clean rain is only slightly acidic, with a pH of about 6, because of \mathrm{CO}_{2} naturally present in the atmosphere. Increasing industrialisation emits more \mathrm{CO}_{2}, sulphur dioxide (\mathrm{SO}_{2}), and oxides of nitrogen. These dissolve in raindrops and fall as acid rain.

Its harmful effects include damage to vegetation, decay of building materials and paints, erosion of ancient monuments by acid reacting with calcium, degraded visibility from fine sulphate and nitrate particles, and harm to fish and aquatic animals from increased water acidity.

Greenhouse effect and global warming. Greenhouses are glass houses that let sunlight in but prevent heat from escaping. Certain gases, especially \mathrm{CO}_{2} and methane (\mathrm{CH}_{4}), accumulate in the atmosphere and prevent heat escape, warming the air. More \mathrm{CO}_{2} is released through industrialisation, fuel burning, and rising population. Less vegetation and deforestation reduce \mathrm{CO}_{2} use in photosynthesis. Over the last three decades, the Earth’s atmospheric temperature has risen by about 0.5°C.

This causes melting snow caps, rising sea levels, and declines in food and fishery production.

Ozone layer depletion. Ozone (\mathrm{O}_{3}) is an allotropic form of oxygen. It forms a sunscreen high in the atmosphere, preventing harmful UV-B rays from reaching the Earth. CFCs, or chlorofluorocarbons, are released from refrigerators, aerosol sprayers, and styrofoam. They rise into the atmosphere and break down into chlorine atoms. These atoms break ozone (\mathrm{O}_{3}) into oxygen (\mathrm{O}_{2}) and O.

Reduced ozone cannot block UV-B rays, which cause sunburn, genetic disorders, skin cancers, and reduced productivity of forests and seas. International Ozone Day is observed on 16 September.

15.8 ABATEMENT OF POLLUTION (abatement : diminishing or nullifying)

Pollution cannot be totally stopped, but several steps can curtail it. The chapter lists concrete control measures:

• Use unleaded petrol and CNG in automobiles
• Switch off automobile engines at red lights and when not in use
• Install tall chimneys in factories with filters and electrostatic precipitators
• Treat industrial effluents before discharging them into water bodies
• Avoid throwing food wastes into open ground or drains
• Set up sewage treatment plants in larger habitations and septic tanks in houses
• Use compost instead of chemical fertilizers, and use pesticides judiciously
• Recycle plastic, metal, and glass; incinerate non-recyclable waste
• Plant trees along roadsides, waste land, and mountainous slopes

Tree planting reduces soil erosion and improves air quality by reducing the amount of \mathrm{CO}_{2} in the atmosphere.

Vehicular standards. Euro and Bharat norms set limits on the levels of emissions given out by all automobiles. Stricter controls are maintained in most large cities. The Government of India has adopted an auto fuel policy to effectively cut down sulphur and nitrogen oxides in automobile exhausts.

What to practise from Pollution Class 10 ICSE

The chapter provides five PROGRESS CHECK blocks spread through the text, with 23 self-test questions in total:

• Progress Check after Brick Kilns — 4 questions (true/false and short answers)
• Progress Check after Thermal Pollution — 1 question (5 true/false statements)
• Progress Check after Pesticides — 2 questions (true/false and listing)
• Progress Check after Noise Pollution — 3 questions (true/false and listing)
• Progress Check after Abatement — 13 questions (true/false, matching, fill-in-blanks)

The chapter closes with four exercise sets: Multiple Choice Type, Very Short Answer Type, Short Answer Type, and Structured/Application/Skill Type. The true/false progress checks test definitions and named examples. The MCQs test pollutant examples like Iodine-131, CFCs, and \mathrm{SO}_{2}. The structured questions test application, such as identifying the kind of pollution in a cartoon and listing its sources and effects.

For more practice material across the subject, visit the Class 10 ICSE Biology hub. You can also browse the full Class 10 ICSE books collection. To verify the official syllabus for this chapter, check the CISCE website.

Pollution Class 10 ICSE frequently asked questions

What is the syllabus for pollution class 10 ICSE biology?

The chapter covers five types of pollution: air, water, soil, radiation, and noise. For each type, you need to know its definition, sources, effects, and control measures. The chapter also covers acid rain, global warming, ozone depletion, and abatement methods. The official syllabus is available on the CISCE website.

What is the difference between biodegradable and non-biodegradable waste?

Biodegradable waste can be broken down by microorganisms into relatively harmless compounds. Examples include paper, vegetable peels, food leftovers, sewage, cow dung, and dried leaves. Non-biodegradable waste cannot be degraded. Examples include plastic, glass, styrofoam, and DDT.

How does thermal pollution kill fish and other aquatic animals?

Industries use water for cooling and release it 8–10°C warmer than the intake. This hot water warms the surrounding water body. The warming harmfully affects animals, even killing fish, and harms the plant life growing in it.

What are the harmful effects of acid rain?

Acid rain damages vegetation by polluting the soil. It decays building materials and paints. It erodes ancient monuments and statues by reacting with calcium. The fine sulphate and nitrate particles degrade visibility and harm human health. Fish and aquatic animals suffer from increased water acidity.

What are Euro and Bharat norms for vehicles?

Euro and Bharat norms set emission limits for all automobiles. Stricter controls apply in most large cities. The Government of India’s auto fuel policy cuts sulphur and nitrogen oxides in automobile exhausts.

Reference: ICSE Class 10 Biology textbook material, chapter 15: Pollution — CISCE-aligned.

More from this book

• Chapter 2: Structure of Chromosomes Cell Cycle and Cell Division
• Chapter 3: Genetics Some Basic Fundamentals
• Chapter 4: Absorption By Roots the Processes Involved
• Chapter 5: Transpiration
• Chapter 6: Photosynthesis
• Chapter 7: The Circulatory System
• Chapter 8: The Excretory System
• Chapter 9: The Nervous System
• Chapter 10: Endocrine Glands
• Chapter 11: The Reproductive System
• Chapter 12: Population
• Chapter 13: Aids to Health
• Chapter 14: Health Organisations