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Summary
All kinds of pollution affect living beings and their surroundings. Pollutants in the environment cause its quality to worsen. The harm from pollution can be small discomforts or serious long-term problems like diseases.
Noise pollution harms both people and the environment. Loud sounds can cause cracks in old buildings and hills. Very strong explosions can break windows and shake buildings. For humans, being around loud noise, especially above 100 decibels, can damage hearing quickly. It can make talking to others or using the phone hard. Loud noise can also stop people from sleeping well. Some people feel mentally unwell due to noise, and doctors agree it can upset our bodies. Noise also affects animals; birds may not go to noisy places, and loud sounds can harm animals like mammals and fish.
Air pollution happens when harmful gases and tiny particles are in the air. This can lead to Global Warming, where gases like Carbon dioxide trap heat, making the Earth warmer. This warming can melt snow earlier, make winters warmer, and cause more water to evaporate, leading to droughts or floods. It affects farming and forests. Air pollution has short-term effects on people, like irritation in the eyes, nose, and throat, or headaches. Long-term effects include serious lung diseases and damage to organs. The Bhopal Gas Tragedy was a terrible accident where toxic gas leak affected many people. Air pollution also harms plants by damaging their leaves and slowing their growth. Animals can get sick if they eat plants covered in pollutants. Even materials like paint, stone, metal, and cloth can be damaged by air pollution.
Water pollution harms humans, aquatic animals, and plants. It can stop plants in water from making food. Two main problems are eutrophication and biomagnification. Eutrophication is when too many nutrients, often from sewage or fertilizers, cause algae to grow too much, using up oxygen so other water creatures die. Biomagnification means harmful chemicals become more concentrated as they move up the food chain; for example, small amounts in water can build up in algae, then fish, then birds that eat the fish. Other pollutants like phosphorus, nitrates, and industrial chemicals kill aquatic life. Hot water from factories also reduces oxygen in water. Oil spills are very dangerous for sea creatures. Humans can get sick from drinking polluted water, with diseases like cholera or typhoid. Heavy metals in water like mercury can cause Minamata disease, leading to numbness and problems with sight and hearing. Cadmium can cause Itai-itai disease.
Soil pollution affects humans and animals through the food they eat. Fertilizers can put too many nitrates in plant leaves. Chemical wastes can pollute underground water. Soil pollution can make land less fertile. Humans can get diseases from eating fruits and vegetables grown in polluted soil. Radioactive materials in the soil can enter the food chain through animals that eat plants. Animal and human waste used as manure can also spread diseases if not treated.
Radioactive pollution comes from nuclear weapon tests, nuclear power plants, and mining radioactive materials. Radiation can damage the environment for hundreds of years. Accidents like the Chernobyl disaster released radioactive gases, harmed many people, and killed plants and animals in an area. One part of the forest near Chernobyl turned reddish-brown and died, so it was called the “Red Forest.” Radiation harms living things by changing their body cells and can cause genetic problems passed to future generations. It can also lead to cancers and other health issues like sterility or bad eyesight.
Textbook solutions (Morning Star/Total)
Multiple-Choice Questions
1. What is the effect of 150 dB of noise?
(a) Pain in ear
(b) Significant change in pulse rate
(c) Permanent damage to hearing
(d) Nausea, vomiting, dizziness
Answer: (b) Significant change in pulse rate
2. Birds avoid migrating to places where noise level is above________
(a) 100 dB
(b) 90 dB
(c) 150 dB
(d) 140 dB
Answer: (a) 100 dB
3. The process of depletion of oxygen from waterbodies occurring either naturally or due to human activities.
(a) Biomagnification
(b) Eutrophication
(c) Bioaccumulation
(d) Pollution
Answer: (b) Eutrophication
4. The increase in the concentration of various toxic substances along the food chain:
(a) Biomagnification
(b) Eutrophication
(c) Bioaccumulation
(d) Pollution
Answer: (a) Biomagnification
5. The phenomenon of concentrated toxic deposition at the higher trophic level is known as:
(a) Biomagnification
(b) Eutrophication
(c) Bioaccumulation
(d) Pollution
Answer: (c) Bioaccumulation
6. Name the disease which resulted in numbness of body parts, vision and hearing problems and abnormal mental behaviour in Japan.
(a) Corona Virus
(b) Minamata
(c) Encephalitis
(d) Fluorosis
Answer: (b) Minamata
7. In Japan, pollution by heavy metal, cadmium, caused the disease called _________
(a) Itai-itai
(b) Minamata
(c) Encephalitis
(d) Fluorosis
Answer: (a) Itai-itai
8. Which disease causes discolouring of dental enamel and black and brown stains on the teeth?
(a) Itai-itai
(b) Minamata
(c) Encephalitis
(d) Fluorosis
Answer: (d) Fluorosis
9. The Municipal Corporation of your city has banned all construction activities from 5 pm to 9 am. Why?
(a) To enable people to sleep.
(b) To reduce the noise produced by the activity.
(c) To reduce the physiological effects of noise pollution.
(d) All of the above.
Answer: (d) All of the above.
Short Answer Questions
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.
2. What major harm is done to human beings by air pollution?
Answer: The major long-term effects of air pollution on human beings are:
(i) chronic respiratory disease;
(ii) lung cancer;
(iii) cardiovascular diseases and coma;
(iv) damage to the nerves, brain, liver and kidneys.
3. How are animals affected by air pollution?
Answer: Animals that feed on grass and plants (coated with polluted particulate matter) are affected with arsenic poisoning. Lead poisoning results in bronchitis and lack of appetite in pet animals.
4. What is the effect of oil spills on marine life?
Answer: Sea water polluted with crude oil leakage causes oil spills which contaminate sea water and lead to the death of marine organisms.
5. What causes waterborne diseases? Name two waterborne diseases.
Answer: Most of the wastewaters, especially sewage, contain pathogens (disease causing organisms) like bacteria, viruses and protozoa. These pathogens enter the human body from contaminated drinking water and are responsible for several waterborne diseases. Two waterborne diseases are cholera and typhoid.
6. In what way does soil pollution affect human beings?
Answer: Soil pollution affects human beings indirectly through food chains. Soil can contain many pathogenic bacteria, viruses and intestinal worms which are transmitted to man by the consumption of fruits and vegetables, causing various types of diseases. Additionally, radioactive fallout on vegetation is a source of radioisotopes which enter the food chain through grazing animals, and some of these radioisotopes can cause abnormalities in human beings. The use of human and animal excreta as manure also pollutes the soil with pathogens that contaminate vegetable crops and affect human health.
7. A landfill was reclaimed and sturdy plants were groom on it instead of crops or fruit trees. Why?
Answer: Soil can contain many pathogenic bacteria, viruses and intestinal worms which are transmitted to man by the consumption of fruits and vegetables, and these pathogens cause various types of diseases. Growing crops or fruit trees on a reclaimed landfill, which might contain such contaminants, could therefore pose a health risk if consumed.
8. Give the impact of radiations on human body.
Answer: Radiations affect living organisms by causing harmful changes in the body cells and at the genetic level. The impact includes:
(i) Genetic Variation: The damage caused by radiations is often seen in the offspring and may be transmitted to many generations.
(ii) Somatic Variation: Short term exposures to radiation can cause damage to organs of the body. The harm done by them includes breast cancer, thyroid cancer, lung cancer and brain cancer, sterility and defective eyesight.
9. Why are nuclear radiations more dangerous than other forms of pollution?
Answer: Nuclear radiations are particularly dangerous because the high level products of nuclear wastes remain in the environment for several hundred years. Furthermore, radiations cause harmful changes at the genetic level, and the damage caused by radiations is often seen in the offspring and may be transmitted to many generations.
10. Crude oil from a refinery has leaked into the Kosasthalaiyar river (north of Chennai), the biodiverse Ennore creek (where many migratory birds come) and the Bay of Bengal. This has caused pollution. List what all could have been impacted and how?
Answer: The crude oil leakage could have impacted the following:
- Marine organisms and aquatic animals in the river, creek, and Bay of Bengal: The oil spill contaminates the water and can lead to the death of these organisms. All chemicals drained into the water have harmful effects on every organism that lives there.
- Aquatic vegetation: The process of photosynthesis can be obstructed due to water pollution, which affects the growth of aquatic vegetation.
- The environment of the Kosasthalaiyar river, Ennore creek, and the Bay of Bengal: These water bodies would be contaminated.
- Migratory birds in the Ennore creek: As organisms that live there or depend on the creek’s ecosystem, they would experience harmful effects from the polluted water and contaminated food sources.
Structured Questions
1. (a) State briefly how is noise pollution detrimental to human health.
Answer: Noise pollution is detrimental to human health in several ways. Continuous exposure to noise levels above 100 dB has an adverse effect on hearing ability, and many workers exposed to the noise of jet aircraft or very noisy workshops for even moderate periods soon develop detectable hearing defects. External sounds can interfere with conversation and use of the telephone, as well as the enjoyment of radio and television programmes, thus affecting the efficiency of offices, schools and other places where communication is of vital importance. Noisy conditions near residential areas at night cause difficulties in sleeping.
Many people complain that noise makes them mentally ill, and doctors and scientists have now medically confirmed that noise disturbs the biological organisms and their respective functions. Fire crackers and other excessive and continuous explosives become physically painful giving rise to neurosis, mental illness, cardiovascular diseases, stomach ulcers and respiratory disorders, thereby, reducing human life. Recent researches have concluded that short exposures to noise (in excess of about 100 dB) can lead to adverse effects on the foetus and cause headache, dizziness and stomach problems. 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. Noise levels in industries cause interference in efficiency and communication and raises possibilities of accidents.
(b) How does air pollution affect human beings?
Answer: The extent to which human beings are affected by air pollution depends on the duration of exposure and the concentration of the pollutants. Air pollution has both short-term and long-term effects on human health. The short-term effects of air pollution are:
(i) irritation in the eyes, nose and throat;
(ii) respiratory infections such as bronchitis and pneumonia;
(iii) headaches, nausea, vomiting, dizziness, convulsions and allergic reactions;
(iv) slurring of speech.
The long-term effects of air pollution are:
(i) chronic respiratory disease;
(ii) lung cancer;
(iii) cardiovascular diseases and coma;
(iv) damage to the nerves, brain, liver and kidneys.
Specific air pollutants have the following effects:
- Carbon monoxide damages lungs, weakens bones, reduces the oxygen carrying capacity of blood and damages heart.
- Sulphur dioxide obstructs breathing, causes irritation of eyes and throat.
- Suspended Particulate Matter (as soot, smoke) causes Asthma, irritation of eyes and cancer.
- Oxides of Nitrogen (nitric oxide, nitrogen dioxide and nitrous oxide) cause acute respiratory infections, bronchitis, lowers resistance to influenza.
- Hydrocarbons affect the respiratory system.
- Ozone causes irritation of eyes and aggravates asthma.
- Lead causes brain damage, affects growth and leads to high blood pressure.
- Arsenic damages kidneys, cause jaundice, lung and skin cancer.
(c) Explain how the accumulation of nutrients and chemicals in the water prove fatal for the marine organisms.
Answer: The accumulation of nutrients and chemicals in water can prove fatal for marine organisms through processes like eutrophication and biomagnification, as well as direct toxicity.
Eutrophication is the process of depletion of oxygen from waterbodies, which takes place due to the introduction of nutrients and chemicals through discharge of domestic sewage, industrial effluents and fertilisers from agricultural fields. The consequent nutrient accumulation results in phenomenal growth of phytoplankton and algae, thereby, reducing the penetration of oxygen, light and heat into the waterbody. As a result, most of the organisms die, draining water of all its oxygen. Phosphorus and Nitrates from fertilisers and detergents contaminate surface water where they act as nutrients and promote the growth of oxygen consuming algae. This in turn, reduces the amount of dissolved oxygen in water and kills fish and other aquatic organisms.
Industrial effluents result in the addition of poisonous chemicals such as Arsenic, Mercury, Cadmium, Lead etc., which kill aquatic organisms. These chemicals may reach human body through contaminated food (i.e., fishes etc.). The accumulation of a small amount of toxic chemicals in water can have a serious impact on the fish that live in it through biomagnification, where the concentration of various toxic substances increases along the food chain.
Sea water polluted with crude oil leakage causes oil spills which contaminate sea water and lead to the death of marine organisms.
(d) With the help of a well labelled diagram explain how the accumulation of toxic substances increases as we move up the food chain.
Answer: The accumulation of toxic substances increases as we move up the food chain through a process called biomagnification. Biomagnification means increasing the concentration of various toxic substances along the food chain. Toxic substances at the level of primary producers get concentrated at each trophic level as they move up the food chain. The phenomenon of concentrated toxic deposition at the higher trophic level is known as bioaccumulation. For example, if there are traces of toxic chemicals in water, then their concentration in algae (primary producers) will be much higher. When fish (primary consumers) eat the algae, the concentration of toxins will increase further in their bodies. If larger fish or birds (secondary or tertiary consumers) eat these fish, the concentration of toxins becomes even higher in their tissues. Therefore, accumulation of a small amount of toxic chemicals in water can have a serious impact on the organisms at higher trophic levels.
See Fig. 18.3 of Morning Star/Total English or click here.
2. (a) State any two effects each of soil pollution on human beings and environment.
Answer: Two effects of soil pollution on the environment are:
(i) Nitrogenous fertilisers produce toxic concentration of nitrate and nitrite in the leaves of plants.
(ii) Land and soil pollution is responsible for loss of fertility and productivity of soil.
Two effects of soil pollution on human beings are:
(i) Soil contains many pathogenic bacteria, viruses and intestinal worms which are transmitted to man by the consumption of fruits and vegetables grown in polluted soil. These pathogens cause various types of diseases.
(ii) Radioactive fallout on vegetation is the source of radioisotopes which enter the food chain through the grazing animals. Some of these radioisotopes cause abnormalities in humans who consume these animals or their products.
(b) Name three common air pollutants and their effects on human health.
Answer: Three common air pollutants and their effects on human health are:
- Carbon monoxide: Damages lungs, weakens bones, reduces the oxygen carrying capacity of blood and damages heart.
- Sulphur dioxide: Obstructs breathing, causes irritation of eyes and throat.
- Lead: Causes brain damage, affects growth and leads to high blood pressure.
(c) What are pathogens? How do they enter human body? Name any three diseases caused by these pathogens.
Answer: Pathogens are disease causing organisms like bacteria, viruses and protozoa. Most of the wastewaters especially sewage contain pathogens.
These pathogens enter the human body from contaminated drinking water. Soil also contains many pathogenic bacteria, viruses and intestinal worms which are transmitted to man by the consumption of fruits and vegetables. Excreta used as manure also contains pathogens that contaminate soil and vegetable crops.
Three diseases caused by these pathogens are cholera, typhoid, and diarrhoea.
(d) State with examples the effects of radiations on the human beings and environment.
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. Other radioactive threats to the environment are the accidents connected with the activities of nuclear reactors, nuclear-powered vessels and satellites, etc. For example, after the Chernobyl accident in 1986, four square kilometres of pine forest near the reactor turned reddish-brown and died, earning the name of the “Red Forest”. Some animals in the worst-hit areas died or stopped reproducing.
On human health, radiations affect living organisms by causing harmful changes in the body cells and at genetic level.
(i) Genetic Variation: The damage caused by radiations is often seen in the offspring and may be transmitted to many generations.
(ii) Somatic Variation: Short term exposures to radiation can cause damage to organs of the body. The harm done by them includes breast cancer, thyroid cancer, lung cancer and brain cancer, sterility and defective eyesight. For example, due to the Chernobyl accident, 237 people suffered from acute radiation sickness, of whom 31 died within the first three months.
Thinking Skills
1. The apparent lack of concern for the effects of pollution seems to be the reason for not implementing plans to prevent pollution. Justify this statement with examples.
Answer: Pollution has severe effects on the environment and human health, yet preventive measures are often delayed or ignored. This shows a lack of urgency in addressing the issue. For instance, despite knowing the health risks of air pollution—such as respiratory infections, cardiovascular diseases, and even cancer—many urban areas continue to allow the use of outdated vehicles and uncontrolled industrial emissions. Similarly, noise pollution, which causes hearing loss, stress, and sleep interference, is often neglected in planning residential zones near traffic-heavy or industrial areas. If authorities were more concerned, stricter regulations and timely interventions would be in place.
2. Which is the most visible effect of pollution on human beings in your city? What are the causes and possible remedies?
Answer: In my city, the most visible effect of pollution is respiratory problems, especially during the winter months. Many people suffer from asthma, bronchitis, and frequent throat infections. The causes include high levels of air pollution from vehicular emissions, construction dust, industrial waste, and the burning of garbage and fossil fuels. Remedies could include stricter vehicle emission controls, encouraging public transport, banning open waste burning, and improving green cover in urban areas to filter air pollutants.
3. Northern India is enveloped in smog in the month of November. List the causes for the same.
Answer: Northern India experiences heavy smog in November due to multiple factors. The main causes include the burning of crop stubble in Punjab and Haryana, which releases large amounts of smoke into the atmosphere. This combines with vehicular emissions, industrial pollution, and construction dust. Weather conditions such as low wind speed and a drop in temperature trap these pollutants near the ground, forming smog. Additionally, the use of firecrackers during festivals further deteriorates air quality.
Extras
Additional MCQs
1. What adverse effect does continuous exposure to noise levels above 100 dB have within a short time?
A. Deafness
B. Nausea
C. Sleep interference
D. Communication difficulty
Answer: A. Deafness
45. Which waste-collection structure did Suresh construct to harvest rainwater?
A. Tanka
B. Baoli
C. Bore well
D. Kul
Answer: A. Tanka
Additional Assertion and Reason
1. Assertion (A): Continuous exposure to noise levels above 100 dB has an adverse effect on hearing ability within a fairly short time.
Reason (R): Many workers who are exposed to the noise of jet aircraft or very noisy workshops for even moderate periods soon develop detectable hearing defects.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R does not explain A.
(c) A is true but R is false
(d) A is false but R is true
Answer: (b) Both A and R are true but R does not explain A.
14. Assertion (A): Fluorosis is caused by cadmium pollution.
Reason (R): Fluorosis causes discolouring of dental enamel.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R does not explain A.
(c) A is true but R is false
(d) A is false but R is true
Answer: (d) A is false but R is true.
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