Selina Concise Solutions for ICSE Class 9 Geography Chapter 18 Effects of Pollution

Exercises

I. Short Answer Questions.

Question 1. How does noise pollution affect animals ?
Answer: Noise from industries, railways, crackers, explosions and commotion in the cities and aircraft, affect animals, birds, mice, fishes and domestic animals. Birds avoid migrating to places where noise level is above 100 dB. The noise emissions caused by supersonic aircraft and railways may cause miscarriage in mammals and fishes as well. Some of the birds have been found to have stopped laying eggs due to noise pollution.
In simple words: Loud noises from things like planes and crackers scare animals and can even stop birds from laying eggs. Some animals are so stressed by noise that they cannot have babies or they choose to move to quieter places.

📝 Teacher's Note: Remind students that many animals have much more sensitive ears than humans, so sounds we find loud can be physically painful for them.

🎯 Exam Tip: To get full marks, mention the specific noise level of "100 dB" and its effect on bird migration.

Question 2. What major harm is done to the human beings by air pollution ?
Answer: It causes irritation in eyes, nose, throat, asthma etc, headache, slurring of speech, lung cancer, damage to nerves, brain fiver and kidneys.
In simple words: Air pollution acts like a slow poison that hurts our breathing system and causes coughing and asthma. It can also travel through our blood to damage the brain and kidneys over time.

📝 Teacher's Note: Use the "smoggy day" analogy to explain eye and throat irritation that students might have felt during winter months.

🎯 Exam Tip: Keywords like "asthma," "lung cancer," and "nerve damage" are essential for scoring full marks.

Question 3. How are the animals affected by air pollution ?
Answer: Polluted grass is eaten by the animals cause arsenic poisoning. Lead poisoning results in bronchitis and lack of appetite in pet animals.
In simple words: When smoke and chemicals from the air settle on the grass, cows and goats eat it and get very sick. Even pets can suffer from breathing problems and stop eating because of lead in the air.

📝 Teacher's Note: Explain that pollution doesn't just stay in the air; it falls onto the ground and enters the food that animals eat.

🎯 Exam Tip: Clearly distinguish between "arsenic poisoning" from eating grass and "lead poisoning" in pets.

Question 4. What is the effect of oil spills on marine life ?
Answer: Sea water polluted with oil leakage causes oil spills which contaminate sea water and lead to the death of marine organisms.
In simple words: When oil leaks from ships, it forms a thick layer on the ocean that stops fish from breathing. This sticky oil is very hard to clean and kills many sea creatures and birds.

📝 Teacher's Note: Use the analogy of a sticky blanket covering the ocean surface that prevents oxygen from reaching the fish.

🎯 Exam Tip: Use the term "contaminate" to describe how oil changes the quality of the seawater.

Question 5. What causes waterborne diseases ? Name two waterborn diseases.
Answer: Phosphates and Nitrates from fertilizers, industrial effluents e.g. Arsenic, Mercury, Cadmium, Lead etc. Gastrointestinal problems, typhoid etc.
In simple words: Chemicals from farms and factories get washed into our rivers and lakes. Drinking or using this dirty water causes serious sickness like typhoid and bad stomach pains.

📝 Teacher's Note: Explain that "effluents" are just a fancy word for liquid waste that factories dump into rivers.

🎯 Exam Tip: Always name specific diseases like "Typhoid" and "Gastrointestinal problems" to complete your answer.

Question 6. In what way does soil pollution affect human beings?
Answer: Human beings are affected through food chains e.g. Nitrogenous fertilizers produce toxic concentration of nitrate and nitrite in the leaves through soil, pollution of soil by underground water polluted by industrial wastes. Eutrophication causes pollution of water and soil making it infertile and unsuitable for plant growth.
In simple words: Soil pollution is dangerous because the vegetables we eat grow in that dirty soil and soak up poisons. These toxins eventually end up inside us, and the soil becomes too poor to grow healthy food anymore.

📝 Teacher's Note: Help students understand the "Food Chain" concept—whatever is in the soil eventually enters our bodies when we eat plants.

🎯 Exam Tip: Mention "Eutrophication" and "toxic concentration in leaves" as key technical terms.

Question 7. Give the impact of radiations on the human body.
Answer: Damage is caused to the offsprings and organs of the body. Several diseases are caused e.g., breast cancer, thyroid cancer, lung cancer, brain cancer and defective eye sight.
In simple words: Radiation is invisible energy that can damage our cells and cause different types of cancer. It can even cause health problems for babies before they are born.

📝 Teacher's Note: Compare radiation to "invisible rays" that are much more powerful and dangerous than sunlight.

🎯 Exam Tip: Mentioning "damage to offsprings" shows you understand that radiation affects future generations.

Question 8. Why are nuclear radiations more dangerous than other forms of pollution ?
Answer: Nuclear radiations survive for a long period upto hundred years resulting in widespread effects to pollute the natural environment.
In simple words: Unlike smoke that clears away, nuclear radiation stays in the ground and air for a very long time. This means it can keep making people and animals sick for hundreds of years.

📝 Teacher's Note: Explain that while we can clean up trash, we cannot easily "clean up" radiation once it spreads.

🎯 Exam Tip: The keyword here is "long period" or "hundred years"—make sure to include the time element.

Question 9. What caused the Bhopal gas tragedy ?
Answer: This was the worst industrial accident on December 3 1984, when about 40 tons of methyl isocyanate (MIC) leaked into the atmosphere from Union Carbides pesticide factory in Bhopal in Madhya Pradesh.
In simple words: A huge cloud of poisonous gas leaked from a factory in Bhopal in the middle of the night. It happened in 1984 and is one of the deadliest industrial accidents ever.

📝 Teacher's Note: This is a key historical event for Indian students. Emphasize that it was a "pesticide factory" to link it to chemical pollution.

🎯 Exam Tip: Remember the full name of the gas: Methyl Isocyanate (MIC) and the date: December 3, 1984.

Question 10. What caused the Chernobyl disaster ?
Answer: This was a radioactive accident in 1986 in Chernobyl in Ukraine on April 26. When a reactor of nuclear power complex at Chernobyl exploded. A massive steam explosion, the core of the reactor combined with water to produce hydrogen exploded blowing toxic radioactive gases into the air.
In simple words: A nuclear power plant in Ukraine exploded because of a mistake during a test. This blast sent a giant cloud of radioactive poison into the sky that traveled across many countries.

📝 Teacher's Note: Explain that Chernobyl was a "nuclear power" accident, which is different from the chemical gas leak at Bhopal.

🎯 Exam Tip: Mention the year "1986" and the location "Ukraine" for a complete answer.

Question 11. What were the after-effects of the Bhopal gas tragedy?
Answer: The tragic after effects were blinding people, choking their breathing and suffocating them, damaged the eyes, lungs and nervous system, upset the urine system and loss of unborn babies, different plant species were also damaged.
In simple words: Many people became blind or had serious trouble breathing after the gas leak. It also damaged their nervous system and plants in the area, showing how deadly the gas was.

📝 Teacher's Note: Discuss how many of these effects lasted for years, affecting the health of survivors' children as well.

🎯 Exam Tip: List at least three specific effects like "blindness," "lung damage," and "loss of unborn babies."

II. Long Answer Questions

Question 1. Noise pollution is detrimental to human health and environment. Discuss.
Answer: Noise pollution has ill effects not only on the human beings but also on the environment.
Human Health
1. Effect on hearing or Deafness : Continuous exposure to noise levels above 100 dB has an adverse effect on hearing ability within a fairly short time. Many workers who are exposed to the noise of jet aircraft or very noisy workshops for even moderate periods soon develop detectable hearing defects.
2. Effect on Communication : External sounds can interfere with conversation and use of the telephone, as well as the enjoyment of radio and television programmes.
3. Repeated interference with sleep : Different people have different depths of sleep and they can adjust to natural sounds. However, noisy conditions near residential areas at night causes difficulties in sleeping.
4. Mental or Physiological Effects : Many people complain that noise makes them mentally ill. Experiments have been performed to attempt to confirm or disprove these claims. Doctors and scientists have now medically confirmed that *noise disturbs the biological organisms and their respective functions.
5. Effects on Physical health and Psychological problems : Noise has little physical effect on the biological performance provided that the noise level is below about 90 dB. Damage to the inner ear may result if continuous noise levels exceed about 100 dB and can lead to physical illness. Psychiatrists and psychologists have in recent researches made observations that noise has certain relation with physical health causing tension resulting in problems such as speech interference, annoyance, fatigue, sleep interference and emotional distress.
Effects on Environment : The noise booms cause cracks in national and archaeological monuments Very high levels of noise are the cause of cracks in hills. High intensity explosions can break glass panes and vibrations in the buildings.
In simple words: Noise pollution isn't just annoying; it can make us deaf and stop us from sleeping or talking. It can even physically crack old buildings and hills, showing that sound has a lot of destructive power.

📝 Teacher's Note: Ask students to name quiet zones (like hospitals or schools) to explain why keeping noise low is a health requirement.

🎯 Exam Tip: Divide your answer into "Human Health" and "Environment" sections to present it clearly.

Question 2. How does air pollution affect human beings and environment
Answer: Air pollution affects human health in various harmful diseases e.g. irritation in eyes, headache, vomiting, respiratory disease, cancer, damage to liver and kidneys. \( NO_2 \) causes harm to plants by yellowing the leaves, \( NO_2 \) causes suppressed growth of plants. Animals eating the polluted grass are affected with arsenic poisoning. Soot, dust and fumes discolour the fabrics arid buildings. The Taj Mahal has suffered damage caused by \( SO_2 \) in the air by getting discoloured and corroded. \( SO_2 \) and \( H_2SO_4 \) causes corrosion of metals like steel, copper and zinc.
In simple words: Air pollution makes people sick and turns plant leaves yellow, stopping them from growing. It also eats away at famous buildings like the Taj Mahal and makes metal objects rust and break faster.

📝 Teacher's Note: Explain that acid rain (formed by \( SO_2 \) and \( H_2SO_4 \)) is what actually "corrodes" the marble of the Taj Mahal.

🎯 Exam Tip: Always use the example of the Taj Mahal when discussing the environmental impact of air pollution.

Question 3. Explain how the accumulation of nutrients and chemicals in the water prove fatal for the marine organisms.
Answer: Eutrophication causes in growth of phytoplankton and algae which reduce the penetration of oxygen, light and heat into the water bodies, so, the marine organisms suffer greatly and mostly die.
In simple words: When too much plant food (nutrients) gets into the water, it makes thick green scum grow on top. This scum blocks sunlight and air, so fish underneath cannot breathe or see, and they eventually die.

📝 Teacher's Note: Use a drawing of a pond covered in green algae to show how it acts like a "lid" on the water.

🎯 Exam Tip: Use the keyword "Eutrophication" to explain the process of algae overgrowth.

Question 4. Explain with the help of a diagram how the accumulation of toxic substances increases as we move up the food chain.
Answer: Nitrogenous fertilizers produce toxic concentration of nitrate and nitrite in the leaves, which are eaten by animals and as ; vegetables by men, which is very harmful for health. Eutrophication is dangerous to marine life and the secondary consumers eating fish etc. are also adversely affected through complicated diseases. Harmful pathogens are transferred to human through vegetables and fruits.
In simple words: This process is called biomagnification. Small amounts of poison in plants build up into very large, dangerous amounts by the time they reach big animals at the top of the food chain.

📝 Teacher's Note: Explain that one big fish eats many small fish, so it gets all the poison from all of them combined.

🎯 Exam Tip: When drawing the diagram, make sure to show the "ppm" (parts per million) increasing as you go higher in the pyramid.

Question 5. Explain the effects of soil pollution on human beings and environment.
Answer: Soil pollution causes contamination of plants which may affect the human health and the scarcity of oxygen disturbs the natural composition of air and air pollution promotes unwanted diseases.
In simple words: Polluted soil makes the plants we eat unsafe for our health. It also changes the balance of gases in the air around us, which can lead to even more sickness.

📝 Teacher's Note: Remind students that healthy soil is like a factory for clean food; if the factory is dirty, the food will be too.

🎯 Exam Tip: Focus on "contamination of plants" as the primary link between soil pollution and human health.

Question 6. Explain with examples the effects of radiations on the environment and on humans.
Answer: Radiations emitting from radioactive materials and the disposal of radioactive wastes cause pollution and damage the environment. The high level products of nuclear wastes remain in the environment for several hundred years. Radioactive threats to the environment are the accidents connected with the activities of nuclear reactors, nuclear powered vessels and satellites, etc. On human being it causes genetic variations, and somatic variation i.e. damage to body organs, breast cancer, thyroid cancer, lung cancer, brain cancer and defective eyesight.
In simple words: Radiations are very dangerous because they can damage our DNA and cause cancers that last for generations. Since nuclear waste stays toxic for hundreds of years, it is a permanent threat to our world.

📝 Teacher's Note: Explain "genetic variation" as changes in our DNA that can be passed down to children, making them sick from birth.

🎯 Exam Tip: List at least three types of cancer and "genetic variations" to get the highest marks.

Question 7. What was the immediate and long term effects of the leakage of MIC gas from the Union Carbide’s pesticide factory in Bhopal ?
Answer: This accident killed 3500 people and 40,000 people were affected in an area of 100 sq. km. Gas leakage did the people blind, loss of body control, loss of unborn babies, damage to brain, kidney, lungs, intestinal diseases, damaging the reproductive ability and plant species.
In simple words: Thousands of people died or were hurt instantly when the poisonous gas leaked. Many people lost their sight or had their internal organs damaged so badly that they suffered for the rest of their lives.

📝 Teacher's Note: Point out that "long term" means the survivors and their children are still dealing with these health problems today.

🎯 Exam Tip: Be sure to mention the death toll (3500) and the specific organs damaged like "brain, kidney, and lungs."

Question 8. What harm did radioactive pollution do in the Chernobyl disaster ?
Answer: After the disaster, four square kilometres of pine forest near the reactor turned reddish brown and died. Horses also died 6 km. away by thyroid damage whole of western USSR and other European countries are contaminated by gamma emitters deposited on the soil. Meat and dairy products were contaminated with Caesium-137. About 7,00,000 people became exposed to Chernobyl radiation, expecting bad health problems.
In simple words: The explosion killed forests and animals very quickly. It also poisoned the grass that cows eat, making milk and meat dangerous for people to consume across many countries.

📝 Teacher's Note: Use the "poisoned milk" example to show how radiation moves from the soil to the plants, then to animals, and finally to humans.

🎯 Exam Tip: Mention "Caesium-137" as the specific radioactive substance that contaminated food products.

Question 9. What Is the impact of toxic compounds on human beings ?
Answer: Toxic Compounds :
• Mercury, Methyl mercury
• Heavy metals, Cadmium
• Arsenic
• Fluoride
Impact on Human beings :
• ‘Minamata’ disease in Japan.
• ‘ltai-itai’ disease in Japan.
• Cancer, ulcers, kidney failure.
• ‘Fluorosis’ discolouring of teeth.
In simple words: Dangerous chemicals in our environment cause scary diseases. For example, mercury poisoning causes Minamata disease, and too much fluoride makes your teeth change color and become weak.

📝 Teacher's Note: "Itai-itai" literally means "it hurts, it hurts" in Japanese—explain that this disease makes bones very brittle and painful.

🎯 Exam Tip: Match the chemical to the disease: Mercury → Minamata, Cadmium → Itai-itai, Fluoride → Fluorosis.